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How to Cite Research Paper – All Formats and Examples

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Research Paper Citation

Research paper citation refers to the act of acknowledging and referencing a previously published work in a scholarly or academic paper . When citing sources, researchers provide information that allows readers to locate the original source, validate the claims or arguments made in the paper, and give credit to the original author(s) for their work.

The citation may include the author’s name, title of the publication, year of publication, publisher, and other relevant details that allow readers to trace the source of the information. Proper citation is a crucial component of academic writing, as it helps to ensure accuracy, credibility, and transparency in research.

How to Cite Research Paper

There are several formats that are used to cite a research paper. Follow the guide for the Citation of a Research Paper:

Last Name, First Name. Title of Book. Publisher, Year of Publication.

Example : Smith, John. The History of the World. Penguin Press, 2010.

Journal Article

Last Name, First Name. “Title of Article.” Title of Journal, vol. Volume Number, no. Issue Number, Year of Publication, pp. Page Numbers.

Example : Johnson, Emma. “The Effects of Climate Change on Agriculture.” Environmental Science Journal, vol. 10, no. 2, 2019, pp. 45-59.

Research Paper

Last Name, First Name. “Title of Paper.” Conference Name, Location, Date of Conference.

Example : Garcia, Maria. “The Importance of Early Childhood Education.” International Conference on Education, Paris, 5-7 June 2018.

Author’s Last Name, First Name. “Title of Webpage.” Website Title, Publisher, Date of Publication, URL.

Example : Smith, John. “The Benefits of Exercise.” Healthline, Healthline Media, 1 March 2022, https://www.healthline.com/health/benefits-of-exercise.

News Article

Last Name, First Name. “Title of Article.” Name of Newspaper, Date of Publication, URL.

Example : Robinson, Sarah. “Biden Announces New Climate Change Policies.” The New York Times, 22 Jan. 2021, https://www.nytimes.com/2021/01/22/climate/biden-climate-change-policies.html.

Author, A. A. (Year of publication). Title of book. Publisher.

Example: Smith, J. (2010). The History of the World. Penguin Press.

Author, A. A., Author, B. B., & Author, C. C. (Year of publication). Title of article. Title of Journal, volume number(issue number), page range.

Example: Johnson, E., Smith, K., & Lee, M. (2019). The Effects of Climate Change on Agriculture. Environmental Science Journal, 10(2), 45-59.

Author, A. A. (Year of publication). Title of paper. In Editor First Initial. Last Name (Ed.), Title of Conference Proceedings (page numbers). Publisher.

Example: Garcia, M. (2018). The Importance of Early Childhood Education. In J. Smith (Ed.), Proceedings from the International Conference on Education (pp. 60-75). Springer.

Author, A. A. (Year, Month Day of publication). Title of webpage. Website name. URL

Example: Smith, J. (2022, March 1). The Benefits of Exercise. Healthline. https://www.healthline.com/health/benefits-of-exercise

Author, A. A. (Year, Month Day of publication). Title of article. Newspaper name. URL.

Example: Robinson, S. (2021, January 22). Biden Announces New Climate Change Policies. The New York Times. https://www.nytimes.com/2021/01/22/climate/biden-climate-change-policies.html

Chicago/Turabian style

Please note that there are two main variations of the Chicago style: the author-date system and the notes and bibliography system. I will provide examples for both systems below.

Author-Date system:

• In-text citation: (Author Last Name Year, Page Number)
• Reference list: Author Last Name, First Name. Year. Title of Book. Place of publication: Publisher.
• In-text citation: (Smith 2005, 28)
• Reference list: Smith, John. 2005. The History of America. New York: Penguin Press.

Notes and Bibliography system:

• Footnote/Endnote citation: Author First Name Last Name, Title of Book (Place of publication: Publisher, Year), Page Number.
• Bibliography citation: Author Last Name, First Name. Title of Book. Place of publication: Publisher, Year.
• Footnote/Endnote citation: John Smith, The History of America (New York: Penguin Press, 2005), 28.
• Bibliography citation: Smith, John. The History of America. New York: Penguin Press, 2005.

JOURNAL ARTICLES:

• Reference list: Author Last Name, First Name. Year. “Article Title.” Journal Title Volume Number (Issue Number): Page Range.
• In-text citation: (Johnson 2010, 45)
• Reference list: Johnson, Mary. 2010. “The Impact of Social Media on Society.” Journal of Communication 60(2): 39-56.
• Footnote/Endnote citation: Author First Name Last Name, “Article Title,” Journal Title Volume Number, Issue Number (Year): Page Range.
• Bibliography citation: Author Last Name, First Name. “Article Title.” Journal Title Volume Number, Issue Number (Year): Page Range.
• Footnote/Endnote citation: Mary Johnson, “The Impact of Social Media on Society,” Journal of Communication 60, no. 2 (2010): 39-56.
• Bibliography citation: Johnson, Mary. “The Impact of Social Media on Society.” Journal of Communication 60, no. 2 (2010): 39-56.

RESEARCH PAPERS:

• Reference list: Author Last Name, First Name. Year. “Title of Paper.” Conference Proceedings Title, Location, Date. Publisher, Page Range.
• In-text citation: (Jones 2015, 12)
• Reference list: Jones, David. 2015. “The Effects of Climate Change on Agriculture.” Proceedings of the International Conference on Climate Change, Paris, France, June 1-3, 2015. Springer, 10-20.
• Footnote/Endnote citation: Author First Name Last Name, “Title of Paper,” Conference Proceedings Title, Location, Date (Place of publication: Publisher, Year), Page Range.
• Bibliography citation: Author Last Name, First Name. “Title of Paper.” Conference Proceedings Title, Location, Date. Place of publication: Publisher, Year.
• Footnote/Endnote citation: David Jones, “The Effects of Climate Change on Agriculture,” Proceedings of the International Conference on Climate Change, Paris, France, June 1-3, 2015 (New York: Springer, 10-20).
• Bibliography citation: Jones, David. “The Effects of Climate Change on Agriculture.” Proceedings of the International Conference on Climate Change, Paris, France, June 1-3, 2015. New York: Springer, 10-20.
• In-text citation: (Author Last Name Year)
• Reference list: Author Last Name, First Name. Year. “Title of Webpage.” Website Name. URL.
• In-text citation: (Smith 2018)
• Reference list: Smith, John. 2018. “The Importance of Recycling.” Environmental News Network. https://www.enn.com/articles/54374-the-importance-of-recycling.
• Footnote/Endnote citation: Author First Name Last Name, “Title of Webpage,” Website Name, URL (accessed Date).
• Bibliography citation: Author Last Name, First Name. “Title of Webpage.” Website Name. URL (accessed Date).
• Footnote/Endnote citation: John Smith, “The Importance of Recycling,” Environmental News Network, https://www.enn.com/articles/54374-the-importance-of-recycling (accessed April 8, 2023).
• Bibliography citation: Smith, John. “The Importance of Recycling.” Environmental News Network. https://www.enn.com/articles/54374-the-importance-of-recycling (accessed April 8, 2023).

NEWS ARTICLES:

• Reference list: Author Last Name, First Name. Year. “Title of Article.” Name of Newspaper, Month Day.
• In-text citation: (Johnson 2022)
• Reference list: Johnson, Mary. 2022. “New Study Finds Link Between Coffee and Longevity.” The New York Times, January 15.
• Footnote/Endnote citation: Author First Name Last Name, “Title of Article,” Name of Newspaper (City), Month Day, Year.
• Bibliography citation: Author Last Name, First Name. “Title of Article.” Name of Newspaper (City), Month Day, Year.
• Footnote/Endnote citation: Mary Johnson, “New Study Finds Link Between Coffee and Longevity,” The New York Times (New York), January 15, 2022.
• Bibliography citation: Johnson, Mary. “New Study Finds Link Between Coffee and Longevity.” The New York Times (New York), January 15, 2022.

Harvard referencing style

Format: Author’s Last name, First initial. (Year of publication). Title of book. Publisher.

Example: Smith, J. (2008). The Art of War. Random House.

Journal article:

Format: Author’s Last name, First initial. (Year of publication). Title of article. Title of journal, volume number(issue number), page range.

Example: Brown, M. (2012). The impact of social media on business communication. Harvard Business Review, 90(12), 85-92.

Research paper:

Format: Author’s Last name, First initial. (Year of publication). Title of paper. In Editor’s First initial. Last name (Ed.), Title of book (page range). Publisher.

Example: Johnson, R. (2015). The effects of climate change on agriculture. In S. Lee (Ed.), Climate Change and Sustainable Development (pp. 45-62). Springer.

Format: Author’s Last name, First initial. (Year, Month Day of publication). Title of page. Website name. URL.

Example: Smith, J. (2017, May 23). The history of the internet. Encyclopedia Britannica. https://www.britannica.com/topic/history-of-the-internet

News article:

Format: Author’s Last name, First initial. (Year, Month Day of publication). Title of article. Title of newspaper, page number (if applicable).

Example: Thompson, E. (2022, January 5). New study finds coffee may lower risk of dementia. The New York Times, A1.

IEEE Format

Author(s). (Year of Publication). Title of Book. Publisher.

Smith, J. K. (2015). The Power of Habit: Why We Do What We Do in Life and Business. Random House.

Journal Article:

Author(s). (Year of Publication). Title of Article. Title of Journal, Volume Number (Issue Number), page numbers.

Johnson, T. J., & Kaye, B. K. (2016). Interactivity and the Future of Journalism. Journalism Studies, 17(2), 228-246.

Author(s). (Year of Publication). Title of Paper. Paper presented at Conference Name, Location.

Jones, L. K., & Brown, M. A. (2018). The Role of Social Media in Political Campaigns. Paper presented at the 2018 International Conference on Social Media and Society, Copenhagen, Denmark.

• Website: Author(s) or Organization Name. (Year of Publication or Last Update). Title of Webpage. Website Name. URL.

Example: National Aeronautics and Space Administration. (2019, August 29). NASA’s Mission to Mars. NASA. https://www.nasa.gov/topics/journeytomars/index.html

• News Article: Author(s). (Year of Publication). Title of Article. Name of News Source. URL.

Example: Johnson, M. (2022, February 16). Climate Change: Is it Too Late to Save the Planet? CNN. https://www.cnn.com/2022/02/16/world/climate-change-planet-scn/index.html

Vancouver Style

In-text citation: Use superscript numbers to cite sources in the text, e.g., “The study conducted by Smith and Johnson^1 found that…”.

Reference list citation: Format: Author(s). Title of book. Edition if any. Place of publication: Publisher; Year of publication.

Example: Smith J, Johnson L. Introduction to Molecular Biology. 2nd ed. New York: Wiley-Blackwell; 2015.

In-text citation: Use superscript numbers to cite sources in the text, e.g., “Several studies have reported that^1,2,3…”.

Reference list citation: Format: Author(s). Title of article. Abbreviated name of journal. Year of publication; Volume number (Issue number): Page range.

Example: Jones S, Patel K, Smith J. The effects of exercise on cardiovascular health. J Cardiol. 2018; 25(2): 78-84.

In-text citation: Use superscript numbers to cite sources in the text, e.g., “Previous research has shown that^1,2,3…”.

Reference list citation: Format: Author(s). Title of paper. In: Editor(s). Title of the conference proceedings. Place of publication: Publisher; Year of publication. Page range.

Example: Johnson L, Smith J. The role of stem cells in tissue regeneration. In: Patel S, ed. Proceedings of the 5th International Conference on Regenerative Medicine. London: Academic Press; 2016. p. 68-73.

In-text citation: Use superscript numbers to cite sources in the text, e.g., “According to the World Health Organization^1…”.

Reference list citation: Format: Author(s). Title of webpage. Name of website. URL [Accessed Date].

Example: World Health Organization. Coronavirus disease (COVID-19) advice for the public. World Health Organization. https://www.who.int/emergencies/disease/novel-coronavirus-2019/advice-for-public [Accessed 3 March 2023].

In-text citation: Use superscript numbers to cite sources in the text, e.g., “According to the New York Times^1…”.

Reference list citation: Format: Author(s). Title of article. Name of newspaper. Year Month Day; Section (if any): Page number.

Example: Jones S. Study shows that sleep is essential for good health. The New York Times. 2022 Jan 12; Health: A8.

Author(s). Title of Book. Edition Number (if it is not the first edition). Publisher: Place of publication, Year of publication.

Example: Smith, J. Chemistry of Natural Products. 3rd ed.; CRC Press: Boca Raton, FL, 2015.

Journal articles:

Author(s). Article Title. Journal Name Year, Volume, Inclusive Pagination.

Example: Garcia, A. M.; Jones, B. A.; Smith, J. R. Selective Synthesis of Alkenes from Alkynes via Catalytic Hydrogenation. J. Am. Chem. Soc. 2019, 141, 10754-10759.

Research papers:

Author(s). Title of Paper. Journal Name Year, Volume, Inclusive Pagination.

Example: Brown, H. D.; Jackson, C. D.; Patel, S. D. A New Approach to Photovoltaic Solar Cells. J. Mater. Chem. 2018, 26, 134-142.

Author(s) (if available). Title of Webpage. Name of Website. URL (accessed Month Day, Year).

Example: National Institutes of Health. Heart Disease and Stroke. National Heart, Lung, and Blood Institute. https://www.nhlbi.nih.gov/health-topics/heart-disease-and-stroke (accessed April 7, 2023).

News articles:

Author(s). Title of Article. Name of News Publication. Date of Publication. URL (accessed Month Day, Year).

Example: Friedman, T. L. The World is Flat. New York Times. April 7, 2023. https://www.nytimes.com/2023/04/07/opinion/world-flat-globalization.html (accessed April 7, 2023).

In AMA Style Format, the citation for a book should include the following information, in this order:

• Title of book (in italics)
• Edition (if applicable)
• Place of publication
• Year of publication

Lodish H, Berk A, Zipursky SL, et al. Molecular Cell Biology. 4th ed. New York, NY: W. H. Freeman; 2000.

In AMA Style Format, the citation for a journal article should include the following information, in this order:

• Title of article
• Abbreviated title of journal (in italics)
• Year of publication; volume number(issue number):page numbers.

Chen H, Huang Y, Li Y, et al. Effects of mindfulness-based stress reduction on depression in adolescents and young adults: a systematic review and meta-analysis. JAMA Netw Open. 2020;3(6):e207081. doi:10.1001/jamanetworkopen.2020.7081

In AMA Style Format, the citation for a research paper should include the following information, in this order:

• Title of paper
• Name of journal or conference proceeding (in italics)
• Volume number(issue number):page numbers.

Bredenoord AL, Kroes HY, Cuppen E, Parker M, van Delden JJ. Disclosure of individual genetic data to research participants: the debate reconsidered. Trends Genet. 2011;27(2):41-47. doi:10.1016/j.tig.2010.11.004

In AMA Style Format, the citation for a website should include the following information, in this order:

• Title of web page or article
• Name of website (in italics)
• Date of publication or last update (if available)
• URL (website address)
• Date of access (month day, year)

Centers for Disease Control and Prevention. How to protect yourself and others. CDC. Published February 11, 2022. Accessed February 14, 2022. https://www.cdc.gov/coronavirus/2019-ncov/prevent-getting-sick/prevention.html

In AMA Style Format, the citation for a news article should include the following information, in this order:

• Name of newspaper or news website (in italics)
• Date of publication

Gorman J. Scientists use stem cells from frogs to build first living robots. The New York Times. January 13, 2020. Accessed January 14, 2020. https://www.nytimes.com/2020/01/13/science/living-robots-xenobots.html

Bluebook Format

One author: Daniel J. Solove, The Future of Reputation: Gossip, Rumor, and Privacy on the Internet (Yale University Press 2007).

Two or more authors: Martha Nussbaum and Saul Levmore, eds., The Offensive Internet: Speech, Privacy, and Reputation (Harvard University Press 2010).

Journal article

One author: Daniel J. Solove, “A Taxonomy of Privacy,” University of Pennsylvania Law Review 154, no. 3 (January 2006): 477-560.

Two or more authors: Ethan Katsh and Andrea Schneider, “The Emergence of Online Dispute Resolution,” Journal of Dispute Resolution 2003, no. 1 (2003): 7-19.

One author: Daniel J. Solove, “A Taxonomy of Privacy,” GWU Law School Public Law Research Paper No. 113, 2005.

Two or more authors: Ethan Katsh and Andrea Schneider, “The Emergence of Online Dispute Resolution,” Cyberlaw Research Paper Series Paper No. 00-5, 2000.

WebsiteElectronic Frontier Foundation, “Surveillance Self-Defense,” accessed April 8, 2023, https://ssd.eff.org/.

News article

One author: Mark Sherman, “Court Deals Major Blow to Net Neutrality Rules,” ABC News, January 14, 2014, https://abcnews.go.com/Politics/wireStory/court-deals-major-blow-net-neutrality-rules-21586820.

Two or more authors: Siobhan Hughes and Brent Kendall, “AT&T Wins Approval to Buy Time Warner,” Wall Street Journal, June 12, 2018, https://www.wsj.com/articles/at-t-wins-approval-to-buy-time-warner-1528847249.

In-Text Citation: (Author’s last name Year of Publication: Page Number)

Example: (Smith 2010: 35)

Reference List Citation: Author’s last name First Initial. Title of Book. Edition. Place of publication: Publisher; Year of publication.

Example: Smith J. Biology: A Textbook. 2nd ed. New York: Oxford University Press; 2010.

Example: (Johnson 2014: 27)

Reference List Citation: Author’s last name First Initial. Title of Article. Abbreviated Title of Journal. Year of publication;Volume(Issue):Page Numbers.

Example: Johnson S. The role of dopamine in addiction. J Neurosci. 2014;34(8): 2262-2272.

Example: (Brown 2018: 10)

Reference List Citation: Author’s last name First Initial. Title of Paper. Paper presented at: Name of Conference; Date of Conference; Place of Conference.

Example: Brown R. The impact of social media on mental health. Paper presented at: Annual Meeting of the American Psychological Association; August 2018; San Francisco, CA.

Example: (World Health Organization 2020: para. 2)

Reference List Citation: Author’s last name First Initial. Title of Webpage. Name of Website. URL. Published date. Accessed date.

Example: World Health Organization. Coronavirus disease (COVID-19) pandemic. WHO website. https://www.who.int/emergencies/disease-coronavirus-2019. Updated August 17, 2020. Accessed September 5, 2021.

Example: (Smith 2019: para. 5)

Reference List Citation: Author’s last name First Initial. Title of Article. Title of Newspaper or Magazine. Year of publication; Month Day:Page Numbers.

Example: Smith K. New study finds link between exercise and mental health. The New York Times. 2019;May 20: A6.

Purpose of Research Paper Citation

The purpose of citing sources in a research paper is to give credit to the original authors and acknowledge their contribution to your work. By citing sources, you are also demonstrating the validity and reliability of your research by showing that you have consulted credible and authoritative sources. Citations help readers to locate the original sources that you have referenced and to verify the accuracy and credibility of your research. Additionally, citing sources is important for avoiding plagiarism, which is the act of presenting someone else’s work as your own. Proper citation also shows that you have conducted a thorough literature review and have used the existing research to inform your own work. Overall, citing sources is an essential aspect of academic writing and is necessary for building credibility, demonstrating research skills, and avoiding plagiarism.

Advantages of Research Paper Citation

There are several advantages of research paper citation, including:

• Giving credit: By citing the works of other researchers in your field, you are acknowledging their contribution and giving credit where it is due.
• Strengthening your argument: Citing relevant and reliable sources in your research paper can strengthen your argument and increase its credibility. It shows that you have done your due diligence and considered various perspectives before drawing your conclusions.
• Demonstrating familiarity with the literature : By citing various sources, you are demonstrating your familiarity with the existing literature in your field. This is important as it shows that you are well-informed about the topic and have done a thorough review of the available research.
• Providing a roadmap for further research: By citing relevant sources, you are providing a roadmap for further research on the topic. This can be helpful for future researchers who are interested in exploring the same or related issues.
• Building your own reputation: By citing the works of established researchers in your field, you can build your own reputation as a knowledgeable and informed scholar. This can be particularly helpful if you are early in your career and looking to establish yourself as an expert in your field.

About the author

Muhammad Hassan

Researcher, Academic Writer, Web developer

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How To Cite a Research Paper: MLA, APA, and Chicago Style

• Posted on January 25, 2022

When you’re writing a research paper, you’ll use a variety of sources to find information. You might find that you end up using other people’s research papers as sources of information for your own work. You need to know how to cite a research paper properly.

Using text citations tells readers where you got your information, and help build a sense of trust, allowing the reader to feel confident that you haven’t falsified the information. You have to prove that you’ve done the research and found data to back up the claims you’re making.

Writing a paper without giving credit to people whose work you’re using is plagiarism. Unless you’re citing a direct quote you want to change the language enough, by putting the quote in your own words, so it sounds like original content. Quetext’s plagiarism checker  helps you search for similar content across the web so you can turn in a completely original paper.

Whether you’re submitting a research paper to school or for publication in a peer-reviewed journal, you’re required to cite your sources. Editors often reread the work of writers and researchers to ensure the information is factual. A teacher or professor will definitely check that your sources are accurate, so using tools like Quetext will help avoid unintentional plagiarism errors or wrongfully cited information.

Why Text Citations are Important

If you don’t have sources to back up your research, others might accuse you of spreading false information or plagiarism. Any journal publishing papers should verify what they’re printing, but ultimately, as the author, the buck stops with you.

In general, it’s a kindness to cite your sources. The people who created them did a lot of work, so it’s wrong to claim ownership of their ideas and information. But it’s also an ethical issue that can have major repercussions.

There have been cases where researchers  make up information  or falsify their sources and must face the consequences. People depend on factual information and don’t react well when they realize you lied to them or falsely paraphrase information.

That’s why it’s common knowledge to write a well-researched paper with text citations. If anyone claims your information is incorrect, you can point them to the source where you found the data. This doesn’t guarantee that the information you cited is correct, but you’ll be able to provide readers with a source of where you gathered your information.

When you’re citing other people’s research papers, make sure the source is legitimate. You should only use peer-reviewed journals so you know the article has gone through edits and fact-checking. Something identified as a research paper that is only on a blog or message board isn’t always a reliable source.

Many students like to use  Wikipedia  because there’s so much information available from one source. However, Wikipedia allows users to edit the information. What you read in a specific entry might not be true. It’s best to scroll down to the works cited and go to the original source yourself. If you can’t find a reliable, original source for the information, you shouldn’t use it.

Using the Various Citation Styles

The information used in any citation is basically the same across each style guide. The formatting and order of some elements may vary, so it’s important to know the difference between Modern Language Association (MLA), American Psychological Association (APA), and Chicago Styles.

The style you use depends on what type of writing you’re doing. All will use these basic elements in some form or another:

Source name

Volume and edition

Publication date

Page numbers

Publisher name

City and country of the publisher

URL and DOI for web pages and digital sources

The date you accessed the material

In addition to a reference list at the end of your work, you’ll also use in-text citations. Whenever you reference an idea or data that isn’t yours, you cite it. Each style has different types of in-text citations as well. Read on to find out about each citation format.

You’ll likely use the  MLA citation guide  if you’re writing papers in the humanities, such as for language arts, literary criticism, cultural studies, and more. The current edition of the MLA Handbook is the ninth because the style constantly evolves. As new technology creates new potential sources, MLA adds information to help students and researchers cite everything correctly.

The MLA Handbook has instructions on how to cite song lyrics, social media posts, and digital images, along with all of the standard research outlets. The book also gives detailed information on how to cite a research paper.

The MLA Handbook includes information about how to format your reference page. Use a 12-pt standard font like Times New Roman, so the text in italics is clearly different from the regular font. Center the title, Works Cited, at the top of the page. Your last name and page number are in the top right corner, and the reference page always comes at the end of your document.

Alphabetize citations according to the last name of the author. Left-align the citations and double-space them with no extra lines between each entry. When a citation goes beyond a single line, use a hanging indent to format it correctly. This lets the reader know it’s still the same citation continuing on.

Now that you know the basic format for the Works Cited page read on to find out how to cite a research paper for inclusion on this list.

Citing a Research Paper in MLA Style

When you’re citing a research paper in MLA style, you start with the author’s full name, putting the last name of the author first, followed by the title of the research paper in quotation marks. Next comes the the title of the journal that published the paper in italics, followed by the volume number, issue number, and date of publication.

You’ll also include the page number since the paper is in a journal with many pages. If you found the source online, include the digital object identifier or DOI. The DOI is a way to give a document a permanent web address so people reading your work can easily find the source.

MLA format also asks you to include the date you accessed online materials. Doing so gives your reader more information about when you read the research if it changed since that date. Here is an example of a research paper citation in MLA style:

Writer, Maria. “My Research Paper.” Research Journal, vol 3, no. 4, 2020, pp. 7-9. doi:12.34/mfs.12.34. Accessed 13 March 2021.

If the work wasn’t published online, you could stop your citation after the page numbers.

Sometimes you might find research papers that aren’t published in a scholarly journal. You can still use those in your work, but the MLA citation will look different. You’ll still put the last name of the author first, but instead of putting the title of the research paper in quotation marks, you’ll put it in italics.

Here is an example of an unpublished research paper citation in MLA style:

Writer, Maria. My Research Paper. 2020, http://websiteused.com . Accessed 13 March 2021.

These two examples show you how to document the source on your Works Cited page. In-text citations look different.

In-Text Citations for a Research Paper in MLA Style

When you’re working with the MLA format, an in-text reference requires a parenthetical citation.

If you refer to someone else’s research in a sentence, either with a direct quote or by paraphrasing, you need to give that author credit. At the end of the sentence where you use the information, you’ll put the author’s information in parenthesis and then put the sentence’s ending punctuation.

You use the author’s last name and the page number where you found the information for in-text citations. Then anyone reading your work can go to your Works Cited page, find the entry by the author’s last name, and access the document themselves. The page number directs them to where you got the specific information, so they don’t have to read the whole paper to find it. Here is an example of an in-text citation in MLA style:

Over 80% of the city’s garbage ended up in the ocean (Writer, 8).

You might mention the author’s name in your sentence. In that case, the parenthetical citation only needs to have the page numbers for reference. Here is an example:

According to Maria Writer, over 80% of the city’s garbage went into the ocean (8).

Researchers in the social science field, like sociology, anthropology, and psychology, use the  APA style  in their work. Like the MLA Handbook, the Publication Manual of the American Psychological Association has gone through changes over the years. It’s currently on the 7th edition.

In addition to helping you understand how to cite research, the Publication Manual of the American Psychological Association has information about how to format your paper to include tables, figures, and headings that often accompany scientific journal articles.

The Publication Manual of the American Psychological Association also tells you how to format your reference page. In MLA style, this is the Works Cited page. For APA style, it’s either the Reference List or Reference Page.

This page uses the same font style as the rest of the paper but starts on its own page with a number in the top right corner. The title of the page is bold and centered at the top and should simply read “References.”

List citations in alphabetical order by author’s last name regardless of the type of source. Each citation is double-spaced and has a hanging indent if it goes beyond one line.

Now that you understand how to properly format your APA reference page, learn how to cite a research paper to include on the list.

Citing a Research Paper in APA Style

When you use a research paper in your work, you need to include it on your APA references page at the end of your document.

An APA citation includes the same information as the MLA format but in a different order. The citation starts with the author’s last name but only uses their first initial. Then comes the year of publication in parenthesis.

The paper’s title follows, then the title of the journal in italics. You also include the journal volume, issue number, and page numbers. As with MLA citations, include a DOI if you found the research paper online. Here is an example of a published research paper cited in APA format:

Writer, M. (2020). My Research Paper. Research Journal, 3(4), 7-9. doi:12.34/mfs.12.34

If the paper isn’t published in a journal, you can still use it in your work with a proper citation. Here is an example:

Writer, M. (2020). My Research Paper [PDF]. Retrieved from http://websiteused.com

In-Text Citations for a Research Paper in APA Style

In-text citations in the APA format differ from MLA style. You still put it in parenthesis, but you include different information. For APA parentheticals, include the author’s last name and the paper’s year of publication. This method applies when you’re summarizing or paraphrasing the author’s idea. Here is an example of an in-text citation for a research paper in APA style:

Over 80% of the city’s garbage went into the ocean (Writer, 2020).

If you’re using a direct quote from the work you need to include the page number so the reader can find the quotation. Here is an example:

Maria Writer said, “Over 80% of the city’s garbage is going into the ocean” (2020, p. 8).

Chicago Style

Chicago Style  got its name from the University of Chicago, where the style originated. Writers use this format for works in the field of history, but you can also use it for the sciences, social sciences, and humanities.

MLA style has a Works Cited page, APA has References, and Chicago Style differs because it includes a Bibliography. The page comes at the end of your work with a page number in the top right corner. The title, “Bibliography,” is bold and centered at the top.

You will single-space your citations, but you’ll add an extra line between each entry. As with the other reference pages, you’ll left-align the work and use a hanging indent when a citation continues onto a second line.

Having an overview of how to format the bibliography will help you understand the citation styles for a research paper.

Citing a Research Paper in Chicago Style

Citations in Chicago Style are a mix of MLA and APA formats. It’s easiest to follow this template:

Writer, Maria. 2020. “My Research Paper.” Research Journal 3 (4): 7-9. doi:12.34/mfs.12.34.

As with other styles, you can reference an unpublished research paper as a document. Here is an example:

Writer, Maria. 2020. My Research Paper. PDF. http://websiteused.com .

In both instances, if there are multiple authors for a paper, list the rest of the authors in normal format. For example:

Author, Alan, Stanley Sample, and Maria Writer. 2020. “My Research Paper.” Research Journal 3 (4): 7-9. doi:12.34/mfs.12.34.

In-Text Citations for a Research Paper in Chicago Style

An in-text citation in Chicago Style is much simpler than both MLA and APA formats. You only need to include the last name of the author and year of publication in parenthesis with no comma in between them. For example:

Almost 80% of the city’s garbage goes into the ocean (Writer 2020).

You’ll include the page number for specificity if you’re quoting the author. Here’s an example:

Maria Writer said, “Over 80% of the city’s garbage is going into the ocean” (2020, 8).

You can also use endnotes in Chicago Style. A citation refers the reader to your source, but an endnote includes a bit of an explanation of why you used it. The information included in an endnote would disrupt the flow of your paper, but it’s still something you want the reader to know.

Make Text Citations Easy

Knowing when you need to cite a source helps you manage your research. Anytime you find information that you’re going to paraphrase, summarize, or quote in your work, you need to cite the source. The full citation will go on your reference page, but you’ll need an in-text citation where you use the information in your paper.

When you’re stating something that is  common knowledge , there’s no need to make a citation. Common knowledge is something that your reader would believe without needing proof. You can check if something is common knowledge by searching for it and finding it mentioned, without a citation, in at least five sources.

Once you learn the basics about citing a research paper in MLA, APA, and Chicago Styles, you’ll feel more confident in your work. The important thing is to pay attention to small details, like capitalization, italics and the use of abbreviations. But there’s no need to do it all on your own—Quetext has a  citation assistant  waiting to help. Give Quetext citation generator a try on your next project.

Sign Up for Quetext Today!

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Home / Guides / Citation Guides / How to Cite Sources

How to Cite Sources

Here is a complete list for how to cite sources. Most of these guides present citation guidance and examples in MLA, APA, and Chicago.

If you’re looking for general information on MLA or APA citations , the EasyBib Writing Center was designed for you! It has articles on what’s needed in an MLA in-text citation , how to format an APA paper, what an MLA annotated bibliography is, making an MLA works cited page, and much more!

MLA Format Citation Examples

The Modern Language Association created the MLA Style, currently in its 9th edition, to provide researchers with guidelines for writing and documenting scholarly borrowings.  Most often used in the humanities, MLA style (or MLA format ) has been adopted and used by numerous other disciplines, in multiple parts of the world.

MLA provides standard rules to follow so that most research papers are formatted in a similar manner. This makes it easier for readers to comprehend the information. The MLA in-text citation guidelines, MLA works cited standards, and MLA annotated bibliography instructions provide scholars with the information they need to properly cite sources in their research papers, articles, and assignments.

• Book Chapter
• Conference Paper
• Documentary
• Encyclopedia
• Google Images
• Kindle Book
• Memorial Inscription
• Museum Exhibit
• Painting or Artwork
• PowerPoint Presentation
• Sheet Music
• Thesis or Dissertation
• YouTube Video

APA Format Citation Examples

The American Psychological Association created the APA citation style in 1929 as a way to help psychologists, anthropologists, and even business managers establish one common way to cite sources and present content.

APA is used when citing sources for academic articles such as journals, and is intended to help readers better comprehend content, and to avoid language bias wherever possible. The APA style (or APA format ) is now in its 7th edition, and provides citation style guides for virtually any type of resource.

Chicago Style Citation Examples

The Chicago/Turabian style of citing sources is generally used when citing sources for humanities papers, and is best known for its requirement that writers place bibliographic citations at the bottom of a page (in Chicago-format footnotes ) or at the end of a paper (endnotes).

The Turabian and Chicago citation styles are almost identical, but the Turabian style is geared towards student published papers such as theses and dissertations, while the Chicago style provides guidelines for all types of publications. This is why you’ll commonly see Chicago style and Turabian style presented together. The Chicago Manual of Style is currently in its 17th edition, and Turabian’s A Manual for Writers of Research Papers, Theses, and Dissertations is in its 8th edition.

Citing Specific Sources or Events

• Declaration of Independence
• Gettysburg Address
• Martin Luther King Jr. Speech
• President Obama’s Farewell Address
• President Trump’s Inauguration Speech
• White House Press Briefing

Additional FAQs

• Citing Archived Contributors
• Citing a Blog
• Citing a Book Chapter
• Citing a Source in a Foreign Language
• Citing an Image
• Citing a Song
• Citing Special Contributors
• Citing a Translated Article
• Citing a Tweet

6 Interesting Citation Facts

The world of citations may seem cut and dry, but there’s more to them than just specific capitalization rules, MLA in-text citations , and other formatting specifications. Citations have been helping researches document their sources for hundreds of years, and are a great way to learn more about a particular subject area.

Ever wonder what sets all the different styles apart, or how they came to be in the first place? Read on for some interesting facts about citations!

1. There are Over 7,000 Different Citation Styles

You may be familiar with MLA and APA citation styles, but there are actually thousands of citation styles used for all different academic disciplines all across the world. Deciding which one to use can be difficult, so be sure to ask you instructor which one you should be using for your next paper.

2. Some Citation Styles are Named After People

While a majority of citation styles are named for the specific organizations that publish them (i.e. APA is published by the American Psychological Association, and MLA format is named for the Modern Language Association), some are actually named after individuals. The most well-known example of this is perhaps Turabian style, named for Kate L. Turabian, an American educator and writer. She developed this style as a condensed version of the Chicago Manual of Style in order to present a more concise set of rules to students.

3. There are Some Really Specific and Uniquely Named Citation Styles

How specific can citation styles get? The answer is very. For example, the “Flavour and Fragrance Journal” style is based on a bimonthly, peer-reviewed scientific journal published since 1985 by John Wiley & Sons. It publishes original research articles, reviews and special reports on all aspects of flavor and fragrance. Another example is “Nordic Pulp and Paper Research,” a style used by an international scientific magazine covering science and technology for the areas of wood or bio-mass constituents.

4. More citations were created on  EasyBib.com  in the first quarter of 2018 than there are people in California.

The US Census Bureau estimates that approximately 39.5 million people live in the state of California. Meanwhile, about 43 million citations were made on EasyBib from January to March of 2018. That’s a lot of citations.

5. “Citations” is a Word With a Long History

The word “citations” can be traced back literally thousands of years to the Latin word “citare” meaning “to summon, urge, call; put in sudden motion, call forward; rouse, excite.” The word then took on its more modern meaning and relevance to writing papers in the 1600s, where it became known as the “act of citing or quoting a passage from a book, etc.”

6. Citation Styles are Always Changing

The concept of citations always stays the same. It is a means of preventing plagiarism and demonstrating where you relied on outside sources. The specific style rules, however, can and do change regularly. For example, in 2018 alone, 46 new citation styles were introduced , and 106 updates were made to exiting styles. At EasyBib, we are always on the lookout for ways to improve our styles and opportunities to add new ones to our list.

Why Citations Matter

Here are the ways accurate citations can help your students achieve academic success, and how you can answer the dreaded question, “why should I cite my sources?”

They Give Credit to the Right People

Citing their sources makes sure that the reader can differentiate the student’s original thoughts from those of other researchers. Not only does this make sure that the sources they use receive proper credit for their work, it ensures that the student receives deserved recognition for their unique contributions to the topic. Whether the student is citing in MLA format , APA format , or any other style, citations serve as a natural way to place a student’s work in the broader context of the subject area, and serve as an easy way to gauge their commitment to the project.

They Provide Hard Evidence of Ideas

Having many citations from a wide variety of sources related to their idea means that the student is working on a well-researched and respected subject. Citing sources that back up their claim creates room for fact-checking and further research . And, if they can cite a few sources that have the converse opinion or idea, and then demonstrate to the reader why they believe that that viewpoint is wrong by again citing credible sources, the student is well on their way to winning over the reader and cementing their point of view.

They Promote Originality and Prevent Plagiarism

The point of research projects is not to regurgitate information that can already be found elsewhere. We have Google for that! What the student’s project should aim to do is promote an original idea or a spin on an existing idea, and use reliable sources to promote that idea. Copying or directly referencing a source without proper citation can lead to not only a poor grade, but accusations of academic dishonesty. By citing their sources regularly and accurately, students can easily avoid the trap of plagiarism , and promote further research on their topic.

They Create Better Researchers

By researching sources to back up and promote their ideas, students are becoming better researchers without even knowing it! Each time a new source is read or researched, the student is becoming more engaged with the project and is developing a deeper understanding of the subject area. Proper citations demonstrate a breadth of the student’s reading and dedication to the project itself. By creating citations, students are compelled to make connections between their sources and discern research patterns. Each time they complete this process, they are helping themselves become better researchers and writers overall.

When is the Right Time to Start Making Citations?

Make in-text/parenthetical citations as you need them.

As you are writing your paper, be sure to include references within the text that correspond with references in a works cited or bibliography. These are usually called in-text citations or parenthetical citations in MLA and APA formats. The most effective time to complete these is directly after you have made your reference to another source. For instance, after writing the line from Charles Dickens’ A Tale of Two Cities : “It was the best of times, it was the worst of times…,” you would include a citation like this (depending on your chosen citation style):

(Dickens 11).

This signals to the reader that you have referenced an outside source. What’s great about this system is that the in-text citations serve as a natural list for all of the citations you have made in your paper, which will make completing the works cited page a whole lot easier. After you are done writing, all that will be left for you to do is scan your paper for these references, and then build a works cited page that includes a citation for each one.

Need help creating an MLA works cited page ? Try the MLA format generator on EasyBib.com! We also have a guide on how to format an APA reference page .

2. Understand the General Formatting Rules of Your Citation Style Before You Start Writing

While reading up on paper formatting may not sound exciting, being aware of how your paper should look early on in the paper writing process is super important. Citation styles can dictate more than just the appearance of the citations themselves, but rather can impact the layout of your paper as a whole, with specific guidelines concerning margin width, title treatment, and even font size and spacing. Knowing how to organize your paper before you start writing will ensure that you do not receive a low grade for something as trivial as forgetting a hanging indent.

Don’t know where to start? Here’s a formatting guide on APA format .

3. Double-check All of Your Outside Sources for Relevance and Trustworthiness First

Collecting outside sources that support your research and specific topic is a critical step in writing an effective paper. But before you run to the library and grab the first 20 books you can lay your hands on, keep in mind that selecting a source to include in your paper should not be taken lightly. Before you proceed with using it to backup your ideas, run a quick Internet search for it and see if other scholars in your field have written about it as well. Check to see if there are book reviews about it or peer accolades. If you spot something that seems off to you, you may want to consider leaving it out of your work. Doing this before your start making citations can save you a ton of time in the long run.

Finished with your paper? It may be time to run it through a grammar and plagiarism checker , like the one offered by EasyBib Plus. If you’re just looking to brush up on the basics, our grammar guides  are ready anytime you are.

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Citation Basics

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• Research Guides
• Schlesinger Library on the History of Women in America
• Archival Materials
• Additional Resources
• Research Tips
• Ask a Schlesinger Librarian

Fundamentals of APA

American Psychological Association (APA) style includes  parenthetical in-text citations  and a  reference list . 

APA uses  parenthetical citations  as its form of in-text citation. Provide a parenthetical citation  before the period  directly following the information you are citing. These citations should correspond to a more detailed citation in the reference list but only need to specify a page number if directly quoting or borrowing from the source material. The essential elements for this in-text citation are the author's last name and the date for the specific publications. The last name may be omitted if the sentence states or makes clear the source material.

APA uses a  reference list ,  an alphabetized list of sources following the end of the book or paper,  for its complete list of sources referenced. This list should be titled "References" in bold and alphabetized by the first item in the citation, which, in most cases, is the author's last name. Each reference from this list must be cited in your paper and vice versa.

Basic Format

Author Last Name, Author First Initial. (Year of publication). Title . Publisher Name.

Print Articles

Author Last Name, Author First Initial, & Author Last Name, Author First Initial. (Year). Article Title. Periodical Title , volume number(issue number), pages.

Electronic Articles

Author Last Name, Author First Initial. (Year). Article Title. Periodical Title , volume number(issue number), pages. doi or static url.

Physical Images/Artwork

Artist Last Name, Artist First Initial. (Year). Artwork Title [medium]. Host Institution Name, City, State, Country. URL of institution.

Electronic Images/Artwork

Artist Last Name, Artist First Initial. (Year). Image Title [medium]. Source Title. URL of image.

In-text Citation Examples

Standard case :

"Lorem   ipsum  dolor sit  amet ,  consectetur   adipiscing   elit" (Last name, 2000, p.10).

If the author is not available , the title of the source may be used:

Lorem   ipsum  dolor sit  amet ,  consectetur   adipiscing   elit ("Source title", 2000, pp.10-11).

If multiple authors cited have the same last name , use the author's first initial along with their last name:

"Lorem   ipsum  dolor sit  amet ,  consectetur   adipiscing   elit" (E. Bronte, 1847, p.10).

Lorem   ipsum  dolor sit  amet ,  consectetur   adipiscing   elit (C. Bronte, 1847, p.10).

Full Citation Examples for the Reference List

Archival material :

Child, J. (1974).  Journal, 1974 . [Unpublished journal].  Papers of Julia Child, 1925-1993(MC 644, item 4).  Schlesinger Library on the History of Women in America, Radcliffe Institute,  https://id.lib.harvard.edu/ead/c/ sch00222c00006 /catalog .

Child, P. (1967). Julia Child at the White House [Photograph]. Schlesinger Library on the History of Women in America, Radcliffe Institute, https://id.lib.harvard.edu/images/olvwork539731/urn-3:RAD.SCHL:4510469/catalog.

Beck, S., Bertholle, L., & Child, J. (1961).  Mastering the art of French cooking.  Knopf.

Child, J. & Child, P. (1968).  The French chef cookbook . Alfred A. Knopf .

Journal article :

Muneal, M. (2011).  Studies in Popular Culture , 34(1), 152–154. www.jstor.org/stable/23416357.

Nussbaum, D. (2005). "In Julia Child's Kitchen, October 5 1998".  Gastronomica , 5(3), 29-38. doi: 10.1525/gfc.2005.5.3.29.

• APA Style website The online version of the APA Style Manual, this website offers to help with the technical elements of formatting in APA as well as writing and citing your work.
• Purdue OWL APA Guide The Purdue Online Writing Lab (OWL) is one of the most complete citation guides available online. The APA Guide explains how to format a paper in APA and breaks down citations by type with numerous examples.
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• Last Updated: Jan 19, 2024 9:31 AM
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APA Citation Style

Citation examples.

• Paper Format
• Style and Grammar Guidelines
• Citation Management Tools
• What's New in the 7th Edition?
• APA Style References Guidelines from the American Psychological Association
• APA Style (OWL - Online Writing Lab, Purdue University)
• Common Reference Examples Handout
• Journal Article
• Magazine Article
• Newspaper Article
• Edited Book Chapter
• Dictionary Entry
• Government Report
• YouTube Video
• Facebook Post
• Webpage on a Website
• Supplemental Reference Examples
• Archival Documents and Collections

Parenthetical citations:  (Grady et al., 2019; Jerrentrup et al., 2018)

Narrative citations:  Grady et al. (2019) and Jerrentrup et al. (2018)

• If a journal article has a DOI, include the DOI in the reference.
• If the journal article does not have a DOI and is from an academic research database, end the reference after the page range (for an explanation of why, see the  database information  page). The reference in this case is the same as for a print journal article.
• Do not include database information in the reference unless the journal article comes from a database that publishes original, proprietary content, such as UpToDate (see an example on the  database information  page).
• If the journal article does not have a DOI but does have a URL that will resolve for readers (e.g., it is from an online journal that is not part of a database), include the URL of the article at the end of the reference.
• If the journal article has an article number instead of a page range, include the article number instead of the page range (as shown in the Jerrentrup et al. example).

Parenthetical citations:  (Rabinowitz, 2019; Sapolsky, 2017)

Narrative citations:  Rabinowitz (2019) and Sapolsky (2017)

• If the book includes a DOI, include the DOI in the reference after the publisher name.
• Do not include the publisher location.
• If the book does not have a DOI and comes from an academic research database, end the book reference after the publisher name. Do not include  database information  in the reference. The reference in this case is the same as for a print book.

Parenthetical citations:  (Schaefer & Shapiro, 2019; Schulman, 2019)

Narrative citations:  Schaefer and Shapiro (2019) and Schulman (2019)

• If a magazine article has a DOI, include the DOI in the reference.
• If the magazine article does not have a DOI and is from an academic research database, end the reference after the page range. Do not include  database information  in the reference. The reference in this case is the same as for a print magazine article.
• If the magazine article does not have a DOI but does have a URL that will resolve for readers (e.g., it is from an online magazine that is not part of a database), include the URL of the article at the end of the reference.
• If the magazine article does not have volume, issue, and/or page numbers (e.g., because it is from an online magazine), omit the missing elements from the reference (as in the Schulman example).

Parenthetical citation:  (Carey, 2019)

Narrative citation:  Carey (2019)

• If the newspaper article is from an academic research database, end the reference after the page range. Do not include  database information  in the reference. The reference in this case is the same as for a print newspaper article.
• If the newspaper article has a URL that will resolve for readers (e.g., it is from an online newspaper), include the URL of the article at the end of the reference.
• If the newspaper article does not have volume, issue, and/or page numbers (e.g., because it is from an online newspaper), omit the missing elements from the reference, as shown in the example.
• If the article is from a news website (e.g., CNN, HuffPost)—one that does not have an associated daily or weekly newspaper—use the format for a  webpage on a website  instead.

Parenthetical citation:  (Aron et al., 2019)

Narrative citation:  Aron et al. (2019)

• If the edited book chapter includes a DOI, include the chapter DOI in the reference after the publisher name.
• If the edited book chapter does not have a DOI and comes from an academic research database, end the edited book chapter reference after the publisher name. Do not include  database information  in the reference. The reference in this case is the same as for a print edited book chapter.
• Do not create references for chapters of authored books. Instead, write a reference for the whole book and cite the chapter in the text if desired (e.g., Kumar, 2017, Chapter 2).

Parenthetical citation:  (Merriam-Webster, n.d.)

Narrative citation:  Merriam-Webster (n.d.)

• Because entries in  Merriam-Webster’s Dictionary  are updated over time and are not archived, include a  retrieval date  in the reference.
• Merriam-Webster is both the author and the publisher, so the name appears in the author element only to avoid repetition.
• To quote a dictionary definition, view the pages on quotations and  how to quote works without page numbers  for guidance. Additionally, here is an example:  Culture  refers to the “customary beliefs, social forms, and material traits of a racial, religious, or social group” (Merriam-Webster, n.d., Definition 1a).

Parenthetical citation:  (National Cancer Institute, 2019)

Narrative citation:  National Cancer Institute (2019)

The specific agency responsible for the report appears as the author. The names of parent agencies not present in the  group author name  appear in the source element as the publisher. This creates concise in-text citations and complete reference list entries.

Parenthetical citation:  (Harvard University, 2019)

Narrative citation:  Harvard University (2019)

• Use the name of the account that uploaded the video as the author.
• If the account did not actually create the work, explain this in the text if it is important for readers to know. However, if that would mean citing a source that appears unauthoritative, you might also look for the author’s YouTube channel, official website, or other social media to see whether the same video is available elsewhere.

Parenthetical citations:  (APA Databases, 2019; Gates, 2019)

Narrative citations:  APA Databases (2019) and Gates (2019)

• Present the name of the individual or group author the same as you would for any other reference. Then provide the Twitter handle (beginning with the @ sign) in square brackets, followed by a period.
• Provide the first 20 words of the tweet as the title. Count a URL, a hashtag, or an emoji as one word each, and include them in the reference if they fall within the first 20 words.
• If the tweet includes an image, a video, a poll, or a thumbnail image with a link, indicate that in brackets after the title: [Image attached], [Video attached], [Thumbnail with link attached].
• The same format used for Twitter is also used for Instagram.  

Parenthetical citation:  (News From Science, 2019)

Narrative citation:  News From Science (2019)

• Provide the first 20 words of the Facebook post as the title. Count a URL or other link, a hashtag, or an emoji as one word each, and include them in the reference if they fall within the first 20 words. 
• If a status update includes images, videos, thumbnail links to outside sources, or content from another Facebook post (such as when sharing a link), indicate that in square brackets.

Parenthetical citations:  (Fagan, 2019; National Institute of Mental Health, 2018; Woodyatt, 2019; World Health Organization, 2018)

Narrative citations:  Fagan (2019), National Institute of Mental Health (2018), Woodyatt (2019), and World Health Organization (2018)

• Provide as specific a  date  as is available on the webpage. This might be a year only; a year and month; or a year, month, and day.
• Italicize the title of a webpage.
• When the author of the webpage and the publisher of the website are the same, omit the publisher name to avoid repetition (as in the World Health Organization example).
• When contents of a page are meant to be updated over time but are not archived, include a  retrieval date  in the reference (as in the Fagan example).
• Use the webpage on a website format for articles from news websites such as CNN and HuffPost (these sites do not have associated daily or weekly newspapers). Use the  newspaper article category  for articles from newspaper websites such as  The New York Times  or  The Washington Post .
• Create a reference to an open educational resources (OER) page only when the materials are available for download directly (i.e., the materials are on the page and/or can be downloaded as PDFs or other files). If you are directed to another website, create a reference to the specific webpage on that website where the materials can be retrieved. Use this format for material in any OER repository, such as OER Commons, OASIS, or MERLOT.
• Do not create a reference or in-text citation for a whole website. To mention a website in general, and not any particular information on that site, provide the name of the website in the text and include the URL in parentheses. For example, you might mention that you used a website to create a survey.

The following supplemental example references are mention in the  Publication Manual:

• retracted journal or magazine article
• edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM)
• edition of the International Statistical Classification of Diseases and Related Health Problems (ICD)
• religious work
• annotated religious work

Archival document and collections are not presented in the  APA Publication Manual, Seventh Edition . This content is available only on the APA Style website .  This guidance has been expanded from the 6th edition.

Archival sources include letters, unpublished manuscripts, limited-circulation brochures and pamphlets, in-house institutional and corporate documents, clippings, and other documents, as well as such nontextual materials as photographs and apparatus, that are in the personal possession of an author, form part of an institutional collection, or are stored in an archive such as the Archives of the History of American Psychology at the University of Akron or the APA Archives. For any documents like these that are available on the open web or via a database (subscription or nonsubscription), follow the reference templates shown in Chapter 10 of the Publication Manual.

The general format for the reference for an archival work includes the author, date, title, and source. The reference examples shown on this page may be modified for collections requiring more or less specific information to locate materials, for different types of collections, or for additional descriptive information (e.g., a translation of a letter). Authors may choose to list correspondence from their own personal collections, but correspondence from other private collections should be listed only with the permission of the collector.

Keep in mind the following principles when creating references to archival documents and collections:

• As with any reference, the purpose is to direct readers to the source, despite the fact that only a single copy of the document may be available and readers may have some difficulty actually seeing a copy.
• Include as much information as is needed to help locate the item with reasonable ease within the repository. For items from collections with detailed finding aids, the name of the collection may be sufficient; for items from collections without finding aids, more information (e.g., call number, box number, file name or number) may be necessary to help locate the item.
• If several letters are cited from the same collection, list the collection as a reference and provide specific identifying information (author, recipient, and date) for each letter in the in-text citations (see Example 3).
• Use square brackets to indicate information that does not appear on the document.
• Use “ca.” (circa) to indicate an estimated date (see Example 5).
• Use italics for titles of archival documents and collections; if the work does not have a title, provide a description in square brackets without italics.
• Separate elements of the source (e.g., the name of a repository, library, university or archive, and the location of the university or archive) with commas. End the source with a period.
• If a publication of limited circulation is available in libraries, the reference may be formatted as usual for published material, without the archival source.
• Note that private letters (vs. those in an archive or repository) are considered personal communications and cited in the text only.

1. Letter from a repository

Frank, L. K. (1935, February 4). [Letter to Robert M. Ogden]. Rockefeller Archive Center (GEB Series 1.3, Box 371, Folder 3877), Tarrytown, NY, United States.

• Parenthetical citation: (Frank, 1935)
• Narrative citation: Frank (1935)
• Because the letter does not have a title, provide a description in square brackets.

2. Letter from a private collection

Zacharius, G. P. (1953, August 15). [Letter to William Rickel (W. Rickel, Trans.)]. Copy in possession of Hendrika Vande Kemp.

• Parenthetical citation: (Zacharius, 1953)
• Narrative citation: Zacharius (1953)
• In this example, Hendrika Vande Kemp is either the author of the paper or the author of the paper has received permission from Hendrika Vande Kemp to cite a letter in Vande Kemp’s private collection in this way. Otherwise, cite a private letter as a  personal communication .

3. Collection of letters from an archive

Allport, G. W. (1930–1967). Correspondence. Gordon W. Allport Papers (HUG 4118.10), Harvard University Archives, Cambridge, MA, United States.

• Parenthetical citation: (Allport, 1930–1967)
• Narrative citation: Allport (1930–1967)

To cite specific letters in the text, provide the author and range of years as shown in the reference list entry, plus details about who wrote the specific letter to whom and when the specific letter was written.

• Parenthetical citation: (Allport, 1930–1967, G. Boring to Allport, December 26, 1937)
• Narrative citation: Allport (1930–1967, Allport to G. Boring, March 1, 1939)
• Use the parenthetical citation format to cite a letter that E. G. Boring wrote to Allport because Allport is the author in the reference. Use either the parenthetical or narrative citation format to cite letters that Allport wrote.

4. Unpublished papers, lectures from an archive or personal collection

Berliner, A. (1959). Notes for a lecture on reminiscences of Wundt and Leipzig. Anna Berliner Memoirs (Box M50), Archives of the History of American Psychology, University of Akron, Akron, OH, United States.

• Parenthetical citation: (Berliner, 1959)
• Narrative citation: Berliner (1959)

5. Archival/historical source for which the author and/or date is known or is reasonably certain but not stated on the document

Allport, A. (presumed). (ca. 1937). Marion Taylor today—by the biographer [Unpublished manuscript]. Marion Taylor Papers, Schlesinger Library, Radcliffe College, Cambridge, MA, United States.

• Parenthetical citation: (Allport, ca. 1937)
• Narrative citation: Allport (ca. 1937)
• Because the author is reasonably certain but not stated on the document, place the word “presumed” in parentheses after the name, followed by a period.
• Because the date is reasonably certain but not stated on the document, the abbreviation “ca.” (which stands for “circa”) appears before the year in parentheses.

6. Archival source with group author

Subcommittee on Mental Hygiene Personnel in School Programs. (1949, November 5–6). Meeting of Subcommittee on Mental Hygiene Personnel in School Programs. David Shakow Papers (M1360), Archives of the History of American Psychology, University of Akron, Akron, OH, United States.

• Parenthetical citation: (Subcommittee on Mental Hygiene Personnel in School Programs, 1949)
• Narrative citation: Subcommittee on Mental Hygiene Personnel in School Programs (1949)

7. Interview recorded and available in an archive

Smith, M. B. (1989, August 12). Interview by C. A. Kiesler [Tape recording]. President’s Oral History Project, American Psychological Association, APA Archives, Washington, DC, United States.

• Parenthetical citation: (Smith, 1989)
• Narrative citation: Smith (1989)
• For interviews and oral histories recorded in an archive, list the interviewee as the author. Include the interviewer’s name in the description.

8. Transcription of a recorded interview, no recording available

Sparkman, C. F. (1973). An oral history with Dr. Colley F. Sparkman/Interviewer: Orley B. Caudill. Mississippi Oral History Program (Vol. 289), University of Southern Mississippi, Hattiesburg, MS, United States.

• Parenthetical citation: (Sparkman, 1973)
• Narrative citation: Sparkman (1973)

9. Newspaper article clipping, historical, in personal collection

Psychoanalysis institute to open. (1948, September 18). [Clipping from an unidentified Dayton, OH, United States, newspaper]. Copy in possession of author.

• Parenthetical citation: (“Psychoanalysis Institute to Open,” 1948)
• Narrative citation: “Psychoanalysis Institute to Open” (1948)
• Use this format only if you are the person who is in possession of the newspaper clipping.

10. Historical publication of limited circulation

Sci-Art Publishers. (1935). Sci-Art publications [Brochure]. Roback Papers (HUGFP 104.50, Box 2, Folder “Miscellaneous Psychological Materials”), Harvard University Archives, Cambridge, MA, United States.

• Parenthetical citation: (Sci-Art Publishers, 1935)
• Narrative citation: Sci-Art Publishers (1935)

11. Archived photographs, no author and no title

[Photographs of Robert M. Yerkes]. (ca. 1917–1954). Robert Mearns Yerkes Papers (Box 137, Folder 2292), Manuscripts and Archives, Yale University Library, New Haven, CT, United States.

• Parenthetical citation: ([Photographs of Robert M. Yerkes], ca. 1917–1954)
• Narrative citation: [Photographs of Robert M. Yerkes] (ca. 1917–1954)
• Because the archived photographs do not have a title, provide a bracketed description instead.
• Because the archived photographs do not have an author, move the bracketed description to the author position of the reference.

12. Microfilm

U.S. Census Bureau. (1880). 1880 U.S. census: Defective, dependent, and delinquent classes schedule: Virginia [Microfilm]. NARA Microfilm Publication T1132 (Rolls 33–34), National Archives and Records Administration, Washington, DC, United States.

• Parenthetical citation: (U.S. Census Bureau, 1880)
• Narrative citation: U.S. Census Bureau (1880)

Read the full APA guidelines on citing ChatGPT 

OpenAI. (2023).  ChatGPT  (Mar 14 version) [Large language model].  https://chat.openai.com/chat

• Parenthetical citation:  (OpenAI, 2023)
• Narrative citation:  OpenAI (2023)

Author:  The author of the model is OpenAI.

Date:  The date is the year of the version you used. Following the template in Section 10.10, you need to include only the year, not the exact date. The version number provides the specific date information a reader might need.

Title:  The name of the model is “ChatGPT,” so that serves as the title and is italicized in your reference, as shown in the template. Although OpenAI labels unique iterations (i.e., ChatGPT-3, ChatGPT-4), they are using “ChatGPT” as the general name of the model, with updates identified with version numbers.

The version number is included after the title in parentheses. The format for the version number in ChatGPT references includes the date because that is how OpenAI is labeling the versions. Different large language models or software might use different version numbering; use the version number in the format the author or publisher provides, which may be a numbering system (e.g., Version 2.0) or other methods.

Bracketed text  is used in references for additional descriptions when they are needed to help a reader understand what’s being cited. References for a number of common sources, such as journal articles and books, do not include bracketed descriptions, but things outside of the typical peer-reviewed system often do. In the case of a reference for ChatGPT, provide the descriptor “Large language model” in square brackets. OpenAI describes ChatGPT-4 as a “large multimodal model,” so that description may be provided instead if you are using ChatGPT-4. Later versions and software or models from other companies may need different descriptions, based on how the publishers describe the model. The goal of the bracketed text is to briefly describe the kind of model to your reader.

Source:  When the publisher name and the author name are the same, do not repeat the publisher name in the source element of the reference, and move directly to the URL. This is the case for ChatGPT. The URL for ChatGPT is  https://chat.openai.com/chat . For other models or products for which you may create a reference, use the URL that links as directly as possible to the source (i.e., the page where you can access the model, not the publisher’s homepage).

What to include and what to exclude

Works included in a reference list.

The reference list provides a reliable way for readers to identify and locate the works cited in a paper. APA Style papers generally include reference lists, not  bibliographies.

In general, each work cited in the text must appear in the reference list, and each work in the reference list must be cited in the text. Check your work carefully before submitting your manuscript or course assignment to ensure no works cited in the text are missing from the reference list and vice versa, with only the following exceptions.

Works Excluded From a Reference List

There are a few kinds of works that are not included in a reference list. Usually a work is not included because readers cannot recover it or because the mention is so broad that readers do not need a reference list entry to understand the use.

Information on works included in a reference list is covered in Sections 2.12 and 8.4 of the  APA Publication Manual, Seventh Edition

*This guidance has been expanded from the 6th edition.*

• Personal communications  such as emails, phone calls, or text messages are cited in the text only, not in the reference list, because readers cannot retrieve personal communications.
• General mentions of whole websites, whole periodicals, and common software and apps in the text do not require in-text citations or reference list entries because the use is broad and the source is familiar.
• The source of an epigraph does not usually appear in the reference list unless the work is a scholarly book or journal. For example, if you open the paper with an inspirational quotation by a famous person, the source of the quotation does not appear in the reference list because the quotation is meant to set the stage for the work, not substantiate a key point.   
• Quotations from research participants in a study you conducted can be presented and discussed in the text but do not need citations or reference list entries. Citations and reference list entries are not necessary because the quotations are part of your original research. They could also compromise participants’ confidentiality, which is an ethical violation.
• References included in a meta-analysis, which are marked with an asterisk in the reference list, may be cited in the text (or not) at the author’s discretion. This exception is relevant only to authors who are conducting a meta-analysis.

DOIs and URLs

The DOI or URL is the final component of a reference list entry. Because so much scholarship is available and/or retrieved online, most reference list entries end with either a DOI or a URL.

• A DOI is a unique alphanumeric string that identifies content and provides a persistent link to its location on the internet. DOIs can be found in database records and the reference lists of published works.
• A URL specifies the location of digital information on the internet and can be found in the address bar of your internet browser. URLs in references should link directly to the cited work when possible.

Follow these guidelines for including DOIs and URLs in references:

• Include a DOI for all works that have a DOI, regardless of whether you used the online version or the print version.
• If a print work does not have a DOI, do not include any DOI or URL in the reference.
• If an online work has both a DOI and a URL, include only the DOI.
• For works without DOIs from websites (not including academic research databases), provide a URL in the reference (as long as the URL will work for readers).
• For works without DOIs from most  academic research databases , do not include a URL or database information in the reference because these works are widely available. The reference should be the same as the reference for a print version of the work.
• For works from databases that publish original, proprietary material available only in that database (such as the UpToDate database) or for works of limited circulation in databases (such as monographs in the ERIC database), include the name of the database or archive and the URL of the work. If the URL requires a login or is session-specific (meaning it will not resolve for readers), provide the URL of the database or archive home page or login page instead of the URL for the work. See the page on including  database information in references  for more information. 
• If the URL is no longer working or no longer provides readers access to the content you intend to cite, follow the guidance for works with  no source .
• Other alphanumeric identifiers such as the International Standard Book Number (ISBN) and the International Standard Serial Number (ISSN) are not included in APA Style references.

Follow these guidelines to format DOIs and URLs:

• Present both DOIs and URLs as hyperlinks (i.e., beginning with “http:” or “https:”).
• Because a hyperlink leads readers directly to the content, it is not necessary to include the words “Retrieved from” or “Accessed from” before a DOI or URL.
• It is acceptable to use either the default display settings for hyperlinks in your word-processing program (e.g., usually blue font, underlined) or plain text that is not underlined.
• Leave links live if the work is to be published or read online.
• Follow the current recommendations of the International DOI Foundation to format DOIs in the reference list, which as of this publication is as follows:

https://doi.org/ xxxxx

• The string “https://doi.org/” is a way of presenting a DOI as a link, and “xxxxx” refers to the DOI number.
• The preferred format of the DOI has changed over time. Although older works use previous formats (e.g., “http:/dx.doi.org/” or “doi:” or “DOI:” before the DOI number), in your reference list, standardize DOIs into the current preferred format for all entries. For example, use  https://doi.org/10.1037/a0040251  in your reference even though that article, published in 2016, presented the number in an older format.
• Copy and paste the DOI or URL from your web browser directly into your reference list to avoid transcription errors. Do not change the capitalization or punctuation of the DOI or URL. Do not add line breaks manually to the hyperlink; it is acceptable if your word-processing program automatically adds a break or moves the hyperlink to its own line.
• Do not add a period after the DOI or URL because this may interfere with link functionality.

When a DOI or URL is long or complex, you may use shortDOIs or shortened URLs if desired.

• Use the  shortDOI service  provided by the International DOI Foundation to create shortDOIs. A work can have only one DOI and only one shortDOI; the shortDOI service will either produce a new shortDOI for a work that has never had one or retrieve an existing shortDOI.
• Some websites provide their own branded shortened URLs, and independent URL shortening services are available as well. Any shortened URL is acceptable in a reference as long as you check the link to ensure that it takes you to the correct location.
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How to Cite a Research Paper

Last Updated: March 29, 2024 Fact Checked

This article was reviewed by Gerald Posner and by wikiHow staff writer, Jennifer Mueller, JD . Gerald Posner is an Author & Journalist based in Miami, Florida. With over 35 years of experience, he specializes in investigative journalism, nonfiction books, and editorials. He holds a law degree from UC College of the Law, San Francisco, and a BA in Political Science from the University of California-Berkeley. He’s the author of thirteen books, including several New York Times bestsellers, the winner of the Florida Book Award for General Nonfiction, and has been a finalist for the Pulitzer Prize in History. He was also shortlisted for the Best Business Book of 2020 by the Society for Advancing Business Editing and Writing. There are 8 references cited in this article, which can be found at the bottom of the page. This article has been fact-checked, ensuring the accuracy of any cited facts and confirming the authority of its sources. This article has been viewed 411,633 times.

When writing a paper for a research project, you may need to cite a research paper you used as a reference. The basic information included in your citation will be the same across all styles. However, the format in which that information is presented is somewhat different depending on whether you're using American Psychological Association (APA), Modern Language Association (MLA), Chicago, or American Medical Association (AMA) style.

Referencing a Research Paper

• In APA style, cite the paper: Last Name, First Initial. (Year). Title. Publisher.
• In Chicago style, cite the paper: Last Name, First Name. “Title.” Publisher, Year.
• In MLA style, cite the paper: Last Name, First Name. “Title.” Publisher. Year.

Citation Help

• For example: "Kringle, K., & Frost, J."

• For example: "Kringle, K., & Frost, J. (2012)."
• If the date, or any other information, are not available, use the guide at https://blog.apastyle.org/apastyle/2012/05/missing-pieces.html .

• For example: "Kringle, K., & Frost, J. (2012). Red noses, warm hearts: The glowing phenomenon among North Pole reindeer."
• If you found the research paper in a database maintained by a university, corporation, or other organization, include any index number assigned to the paper in parentheses after the title. For example: "Kringle, K., & Frost, J. (2012). Red noses, warm hearts: The glowing phenomenon among North Pole reindeer. (Report No. 1234)."

• For example: "Kringle, K., & Frost, J. (2012). Red noses, warm hearts: The glowing phenomenon among North Pole reindeer. (Report No. 1234). Retrieved from Alaska University Library Archives, December 24, 2017."

• For example: "(Kringle & Frost, 2012)."
• If there was no date on the research paper, use the abbreviation n.d. : "(Kringle & Frost, n.d.)."

• For example: "Kringle, Kris, and Jack Frost."

• For example: "Kringle, Kris, and Jack Frost. "Red Noses, Warm Hearts: The Glowing Phenomenon among North Pole Reindeer." Master's thesis."

• For example: "Kringle, Kris, and Jack Frost. "Red Noses, Warm Hearts: The Glowing Phenomenon among North Pole Reindeer." Master's thesis, Alaska University, 2012."

• For example: "Kringle, Kris, and Jack Frost. "Red Noses, Warm Hearts: The Glowing Phenomenon among North Pole Reindeer." Master's thesis, Alaska University, 2012. Accessed at https://www.northpolemedical.com/raising_rudolf."

• Footnotes are essentially the same as the full citation, although the first and last names of the authors aren't inverted.
• For parenthetical citations, Chicago uses the Author-Date format. For example: "(Kringle and Frost 2012)."

• For example: "Kringle, Kris, and Frost, Jack."

• For example: "Kringle, Kris, and Frost, Jack. "Red Noses, Warm Hearts: The Glowing Phenomenon Among North Pole Reindeer.""

• For example, suppose you found the paper in a collection of paper housed in university archives. Your citation might be: "Kringle, Kris, and Frost, Jack. "Red Noses, Warm Hearts: The Glowing Phenomenon Among North Pole Reindeer." Master's Theses 2000-2010. University of Alaska Library Archives. Accessed December 24, 2017."

• For example: "(Kringle & Frost, p. 33)."

• For example: "Kringle K, Frost J."

• For example: "Kringle K, Frost J. Red noses, warm hearts: The glowing phenomenon among North Pole reindeer."

• For example: "Kringle K, Frost J. Red noses, warm hearts: The glowing phenomenon among North Pole reindeer. Nat Med. 2012; 18(9): 1429-1433."

• For example, if you're citing a paper presented at a conference, you'd write: "Kringle K, Frost J. Red noses, warm hearts: The glowing phenomenon among North Pole reindeer. Oral presentation at Arctic Health Association Annual Summit; December, 2017; Nome, Alaska."
• To cite a paper you read online, you'd write: "Kringle K, Frost J. Red noses, warm hearts: The glowing phenomenon among North Pole reindeer. https://www.northpolemedical.com/raising_rudolf"

• For example: "According to Kringle and Frost, these red noses indicate a subspecies of reindeer native to Alaska and Canada that have migrated to the North Pole and mingled with North Pole reindeer. 1 "

Community Q&A

• If you used a manual as a source in your research paper, you'll need to learn how to cite the manual also. Thanks Helpful 0 Not Helpful 0
• If you use any figures in your research paper, you'll also need to know the proper way to cite them in MLA, APA, AMA, or Chicago. Thanks Helpful 0 Not Helpful 0

You Might Also Like

• ↑ https://askus.library.wwu.edu/faq/116659
• ↑ https://guides.libraries.psu.edu/apaquickguide/intext
• ↑ https://owl.purdue.edu/owl/research_and_citation/chicago_manual_17th_edition/cmos_formatting_and_style_guide/general_format.html
• ↑ https://libanswers.snhu.edu/faq/48009
• ↑ https://www.chicagomanualofstyle.org/tools_citationguide/citation-guide-2.html
• ↑ https://owl.purdue.edu/owl/research_and_citation/mla_style/mla_formatting_and_style_guide/mla_in_text_citations_the_basics.html
• ↑ https://morningside.libguides.com/MLA8/location
• ↑ https://owl.purdue.edu/owl/research_and_citation/ama_style/index.html

About This Article

To cite a paper APA style, start with the author's last name and first initial, and the year of publication. Then, list the title of the paper, where you found it, and the date that you accessed it. In a paper, use a parenthetical reference with the last name of the author and the publication year. For an MLA citation, list the author's last name and then first name and the title of the paper in quotations. Include where you accessed the paper and the date you retrieved it. In your paper, use a parenthetical reference with the author's last name and the page number. Keep reading for tips on Chicago and AMA citations and exceptions to the citation rules! Did this summary help you? Yes No

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Citing Sources: What are citations and why should I use them?

What is a citation.

Citations are a way of giving credit when certain material in your work came from another source. It also gives your readers the information necessary to find that source again-- it provides an important roadmap to your research process. Whenever you use sources such as books, journals or websites in your research, you must give credit to the original author by citing the source. 

Why do researchers cite?

Scholarship is a conversation  and scholars use citations not only to  give credit  to original creators and thinkers, but also to  add strength and authority  to their own work.  By citing their sources, scholars are  placing their work in a specific context  to show where they “fit” within the larger conversation.  Citations are also a great way to  leave a trail  intended to help others who may want to explore the conversation or use the sources in their own work.

In short, citations

(1) give credit

(2) add strength and authority to your work

(3) place your work in a specific context

(4) leave a trail for other scholars

"Good citations should reveal your sources, not conceal them. They should honeslty reflect the research you conducted." (Lipson 4)

Lipson, Charles. "Why Cite?"  Cite Right: A Quick Guide to Citation Styles--MLA, APA, Chicago, the Sciences, Professions, and More . Chicago: U of Chicago, 2006. Print.

What does a citation look like?

Different subject disciplines call for citation information to be written in very specific order, capitalization, and punctuation. There are therefore many different style formats. Three popular citation formats are MLA Style (for humanities articles) and APA or Chicago (for social sciences articles).

MLA style (print journal article):  

Whisenant, Warren A. "How Women Have Fared as Interscholastic Athletic Administrators Since the Passage of Title IX." Sex Roles Vol. 49.3 (2003): 179-182.

APA style (print journal article):

Whisenant, W. A. (2003) How Women Have Fared as Interscholastic Athletic Administrators Since the Passage of Title IX. Sex Roles , 49 (3), 179-182.

Chicago style (print journal article):

Whisenant, Warren A. "How Women Have Fared as Interscholastic Athletic Administrators Since the Passage of Title IX." Sex Roles 49, no. 3 (2003): 179-182.

No matter which style you use, all citations require the same basic information:

• Author or Creator
• Container (e.g., Journal or magazine, website, edited book)
• Date of creation or publication
• Publisher 

You are most likely to have easy access to all of your citation information when you find it in the first place. Take note of this information up front, and it will be much easier to cite it effectively later.

• << Previous: Basics of Citing
• Next: When should I use a citation? >>
• Last Updated: Oct 24, 2023 3:46 PM
• URL: https://guides.lib.uw.edu/research/citations

University Library

Start your research.

• Research Process
• Find Background Info
• Find Sources through the Library
• Evaluate Your Info
• Cite Your Sources
• Evaluate, Write & Cite

• is the right thing to do  to give credit to those who had the idea
• shows that you have read and understand  what experts have had to say about your topic
• helps people find the sources  that you used in case they want to read more about the topic
• provides   evidence  for your arguments
• is professional and  standard practice   for students and scholars

What is a Citation?

A citation identifies for the reader the original source for an idea, information, or image that is referred to in a work.

• In the body of a paper, the  in-text citation  acknowledges the source of information used.
• At the end of a paper, the citations are compiled on a  References  or  Works Cited  list. A basic citation includes the author, title, and publication information of the source. 

From:  Lemieux  Library,  University  of Seattle 

Why Should You Cite?

Quoting Are you quoting two or more consecutive words from a source? Then the original source should be cited and the words or phrase placed in quotes. 

Paraphrasing If an idea or information comes from another source,  even if you put it in your own words , you still need to credit the source.  General vs. Unfamiliar Knowledge You do not need to cite material which is accepted common knowledge. If in doubt whether your information is common knowledge or not, cite it. Formats We usually think of books and articles. However, if you use material from web sites, films, music, graphs, tables, etc. you'll also need to cite these as well.

Plagiarism is presenting the words or ideas of someone else as your own without proper acknowledgment of the source. When you work on a research paper and use supporting material from works by others, it's okay to quote people and use their ideas, but you do need to correctly credit them. Even when you summarize or paraphrase information found in books, articles, or Web pages, you must acknowledge the original author.

Citation Style Help

Helpful links:

• MLA ,  Works Cited : A Quick Guide (a template of core elements)
• CSE  (Council of Science Editors)

For additional writing resources specific to styles listed here visit the  Purdue OWL Writing Lab

Citation and Bibliography Resources

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MLA In-Text Citations: The Basics

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MLA (Modern Language Association) style is most commonly used to write papers and cite sources within the liberal arts and humanities. This resource, updated to reflect the MLA Handbook (9 th ed.), offers examples for the general format of MLA research papers, in-text citations, endnotes/footnotes, and the Works Cited page.

Guidelines for referring to the works of others in your text using MLA style are covered throughout the  MLA Handbook  and in chapter 7 of the  MLA Style Manual . Both books provide extensive examples, so it's a good idea to consult them if you want to become even more familiar with MLA guidelines or if you have a particular reference question.

Basic in-text citation rules

In MLA Style, referring to the works of others in your text is done using parenthetical citations . This method involves providing relevant source information in parentheses whenever a sentence uses a quotation or paraphrase. Usually, the simplest way to do this is to put all of the source information in parentheses at the end of the sentence (i.e., just before the period). However, as the examples below will illustrate, there are situations where it makes sense to put the parenthetical elsewhere in the sentence, or even to leave information out.

General Guidelines

• The source information required in a parenthetical citation depends (1) upon the source medium (e.g. print, web, DVD) and (2) upon the source’s entry on the Works Cited page.
• Any source information that you provide in-text must correspond to the source information on the Works Cited page. More specifically, whatever signal word or phrase you provide to your readers in the text must be the first thing that appears on the left-hand margin of the corresponding entry on the Works Cited page.

In-text citations: Author-page style

MLA format follows the author-page method of in-text citation. This means that the author's last name and the page number(s) from which the quotation or paraphrase is taken must appear in the text, and a complete reference should appear on your Works Cited page. The author's name may appear either in the sentence itself or in parentheses following the quotation or paraphrase, but the page number(s) should always appear in the parentheses, not in the text of your sentence. For example:

Both citations in the examples above, (263) and (Wordsworth 263), tell readers that the information in the sentence can be located on page 263 of a work by an author named Wordsworth. If readers want more information about this source, they can turn to the Works Cited page, where, under the name of Wordsworth, they would find the following information:

Wordsworth, William. Lyrical Ballads . Oxford UP, 1967.

In-text citations for print sources with known author

For print sources like books, magazines, scholarly journal articles, and newspapers, provide a signal word or phrase (usually the author’s last name) and a page number. If you provide the signal word/phrase in the sentence, you do not need to include it in the parenthetical citation.

These examples must correspond to an entry that begins with Burke, which will be the first thing that appears on the left-hand margin of an entry on the Works Cited page:

Burke, Kenneth. Language as Symbolic Action: Essays on Life, Literature, and Method . University of California Press, 1966.

In-text citations for print sources by a corporate author

When a source has a corporate author, it is acceptable to use the name of the corporation followed by the page number for the in-text citation. You should also use abbreviations (e.g., nat'l for national) where appropriate, so as to avoid interrupting the flow of reading with overly long parenthetical citations.

In-text citations for sources with non-standard labeling systems

If a source uses a labeling or numbering system other than page numbers, such as a script or poetry, precede the citation with said label. When citing a poem, for instance, the parenthetical would begin with the word “line”, and then the line number or range. For example, the examination of William Blake’s poem “The Tyger” would be cited as such:

The speaker makes an ardent call for the exploration of the connection between the violence of nature and the divinity of creation. “In what distant deeps or skies. / Burnt the fire of thine eyes," they ask in reference to the tiger as they attempt to reconcile their intimidation with their relationship to creationism (lines 5-6).

Longer labels, such as chapters (ch.) and scenes (sc.), should be abbreviated.

In-text citations for print sources with no known author

When a source has no known author, use a shortened title of the work instead of an author name, following these guidelines.

Place the title in quotation marks if it's a short work (such as an article) or italicize it if it's a longer work (e.g. plays, books, television shows, entire Web sites) and provide a page number if it is available.

Titles longer than a standard noun phrase should be shortened into a noun phrase by excluding articles. For example, To the Lighthouse would be shortened to Lighthouse .

If the title cannot be easily shortened into a noun phrase, the title should be cut after the first clause, phrase, or punctuation:

In this example, since the reader does not know the author of the article, an abbreviated title appears in the parenthetical citation, and the full title of the article appears first at the left-hand margin of its respective entry on the Works Cited page. Thus, the writer includes the title in quotation marks as the signal phrase in the parenthetical citation in order to lead the reader directly to the source on the Works Cited page. The Works Cited entry appears as follows:

"The Impact of Global Warming in North America." Global Warming: Early Signs . 1999. www.climatehotmap.org/. Accessed 23 Mar. 2009.

If the title of the work begins with a quotation mark, such as a title that refers to another work, that quote or quoted title can be used as the shortened title. The single quotation marks must be included in the parenthetical, rather than the double quotation.

Parenthetical citations and Works Cited pages, used in conjunction, allow readers to know which sources you consulted in writing your essay, so that they can either verify your interpretation of the sources or use them in their own scholarly work.

Author-page citation for classic and literary works with multiple editions

Page numbers are always required, but additional citation information can help literary scholars, who may have a different edition of a classic work, like Marx and Engels's  The Communist Manifesto . In such cases, give the page number of your edition (making sure the edition is listed in your Works Cited page, of course) followed by a semicolon, and then the appropriate abbreviations for volume (vol.), book (bk.), part (pt.), chapter (ch.), section (sec.), or paragraph (par.). For example:

Author-page citation for works in an anthology, periodical, or collection

When you cite a work that appears inside a larger source (for instance, an article in a periodical or an essay in a collection), cite the author of the  internal source (i.e., the article or essay). For example, to cite Albert Einstein's article "A Brief Outline of the Theory of Relativity," which was published in  Nature  in 1921, you might write something like this:

See also our page on documenting periodicals in the Works Cited .

Citing authors with same last names

Sometimes more information is necessary to identify the source from which a quotation is taken. For instance, if two or more authors have the same last name, provide both authors' first initials (or even the authors' full name if different authors share initials) in your citation. For example:

Citing a work by multiple authors

For a source with two authors, list the authors’ last names in the text or in the parenthetical citation:

Corresponding Works Cited entry:

Best, David, and Sharon Marcus. “Surface Reading: An Introduction.” Representations , vol. 108, no. 1, Fall 2009, pp. 1-21. JSTOR, doi:10.1525/rep.2009.108.1.1

For a source with three or more authors, list only the first author’s last name, and replace the additional names with et al.

Franck, Caroline, et al. “Agricultural Subsidies and the American Obesity Epidemic.” American Journal of Preventative Medicine , vol. 45, no. 3, Sept. 2013, pp. 327-333.

Citing multiple works by the same author

If you cite more than one work by an author, include a shortened title for the particular work from which you are quoting to distinguish it from the others. Put short titles of books in italics and short titles of articles in quotation marks.

Citing two articles by the same author :

Citing two books by the same author :

Additionally, if the author's name is not mentioned in the sentence, format your citation with the author's name followed by a comma, followed by a shortened title of the work, and, when appropriate, the page number(s):

Citing multivolume works

If you cite from different volumes of a multivolume work, always include the volume number followed by a colon. Put a space after the colon, then provide the page number(s). (If you only cite from one volume, provide only the page number in parentheses.)

Citing the Bible

In your first parenthetical citation, you want to make clear which Bible you're using (and underline or italicize the title), as each version varies in its translation, followed by book (do not italicize or underline), chapter, and verse. For example:

If future references employ the same edition of the Bible you’re using, list only the book, chapter, and verse in the parenthetical citation:

John of Patmos echoes this passage when describing his vision (Rev. 4.6-8).

Citing indirect sources

Sometimes you may have to use an indirect source. An indirect source is a source cited within another source. For such indirect quotations, use "qtd. in" to indicate the source you actually consulted. For example:

Note that, in most cases, a responsible researcher will attempt to find the original source, rather than citing an indirect source.

Citing transcripts, plays, or screenplays

Sources that take the form of a dialogue involving two or more participants have special guidelines for their quotation and citation. Each line of dialogue should begin with the speaker's name written in all capitals and indented half an inch. A period follows the name (e.g., JAMES.) . After the period, write the dialogue. Each successive line after the first should receive an additional indentation. When another person begins speaking, start a new line with that person's name indented only half an inch. Repeat this pattern each time the speaker changes. You can include stage directions in the quote if they appear in the original source.

Conclude with a parenthetical that explains where to find the excerpt in the source. Usually, the author and title of the source can be given in a signal phrase before quoting the excerpt, so the concluding parenthetical will often just contain location information like page numbers or act/scene indicators.

Here is an example from O'Neill's  The Iceman Cometh.

WILLIE. (Pleadingly) Give me a drink, Rocky. Harry said it was all right. God, I need a drink.

ROCKY. Den grab it. It's right under your nose.

WILLIE. (Avidly) Thanks. (He takes the bottle with both twitching hands and tilts it to his lips and gulps down the whiskey in big swallows.) (1.1)

Citing non-print or sources from the Internet

With more and more scholarly work published on the Internet, you may have to cite sources you found in digital environments. While many sources on the Internet should not be used for scholarly work (reference the OWL's  Evaluating Sources of Information  resource), some Web sources are perfectly acceptable for research. When creating in-text citations for electronic, film, or Internet sources, remember that your citation must reference the source on your Works Cited page.

Sometimes writers are confused with how to craft parenthetical citations for electronic sources because of the absence of page numbers. However, these sorts of entries often do not require a page number in the parenthetical citation. For electronic and Internet sources, follow the following guidelines:

• Include in the text the first item that appears in the Work Cited entry that corresponds to the citation (e.g. author name, article name, website name, film name).
• Do not provide paragraph numbers or page numbers based on your Web browser’s print preview function.
• Unless you must list the Web site name in the signal phrase in order to get the reader to the appropriate entry, do not include URLs in-text. Only provide partial URLs such as when the name of the site includes, for example, a domain name, like  CNN.com  or  Forbes.com,  as opposed to writing out http://www.cnn.com or http://www.forbes.com.

Miscellaneous non-print sources

Two types of non-print sources you may encounter are films and lectures/presentations:

In the two examples above “Herzog” (a film’s director) and “Yates” (a presentor) lead the reader to the first item in each citation’s respective entry on the Works Cited page:

Herzog, Werner, dir. Fitzcarraldo . Perf. Klaus Kinski. Filmverlag der Autoren, 1982.

Yates, Jane. "Invention in Rhetoric and Composition." Gaps Addressed: Future Work in Rhetoric and Composition, CCCC, Palmer House Hilton, 2002. Address.

Electronic sources

Electronic sources may include web pages and online news or magazine articles:

In the first example (an online magazine article), the writer has chosen not to include the author name in-text; however, two entries from the same author appear in the Works Cited. Thus, the writer includes both the author’s last name and the article title in the parenthetical citation in order to lead the reader to the appropriate entry on the Works Cited page (see below).

In the second example (a web page), a parenthetical citation is not necessary because the page does not list an author, and the title of the article, “MLA Formatting and Style Guide,” is used as a signal phrase within the sentence. If the title of the article was not named in the sentence, an abbreviated version would appear in a parenthetical citation at the end of the sentence. Both corresponding Works Cited entries are as follows:

Taylor, Rumsey. "Fitzcarraldo." Slant , 13 Jun. 2003, www.slantmagazine.com/film/review/fitzcarraldo/. Accessed 29 Sep. 2009. 

"MLA Formatting and Style Guide." The Purdue OWL , 2 Aug. 2016, owl.english.purdue.edu/owl/resource/747/01/. Accessed 2 April 2018.

Multiple citations

To cite multiple sources in the same parenthetical reference, separate the citations by a semi-colon:

Time-based media sources

When creating in-text citations for media that has a runtime, such as a movie or podcast, include the range of hours, minutes and seconds you plan to reference. For example: (00:02:15-00:02:35).

When a citation is not needed

Common sense and ethics should determine your need for documenting sources. You do not need to give sources for familiar proverbs, well-known quotations, or common knowledge (For example, it is expected that U.S. citizens know that George Washington was the first President.). Remember that citing sources is a rhetorical task, and, as such, can vary based on your audience. If you’re writing for an expert audience of a scholarly journal, for example, you may need to deal with expectations of what constitutes “common knowledge” that differ from common norms.

Other Sources

The MLA Handbook describes how to cite many different kinds of authors and content creators. However, you may occasionally encounter a source or author category that the handbook does not describe, making the best way to proceed can be unclear.

In these cases, it's typically acceptable to apply the general principles of MLA citation to the new kind of source in a way that's consistent and sensible. A good way to do this is to simply use the standard MLA directions for a type of source that resembles the source you want to cite.

You may also want to investigate whether a third-party organization has provided directions for how to cite this kind of source. For example, Norquest College provides guidelines for citing Indigenous Elders and Knowledge Keepers⁠ —an author category that does not appear in the MLA Handbook . In cases like this, however, it's a good idea to ask your instructor or supervisor whether using third-party citation guidelines might present problems.

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Why are citations important?

Apa citations.

Good research projects combine data from a variety of sources and carefully document the sources of information and ideas. Research documentation usually appears in two parts: short in-text citations occurring within the actual paper and a longer, complete list of works at the end of the paper called a bibliography, reference list, or works cited page. 

Besides giving credit to the source of information or ideas, there are other great reasons to cite in your research project:

• Persuasiveness - Your writing will be more persuasive if you cite the research on which you based your own conclusions and arguments.
• Sharing - Citations make it possible for your professor and other readers to examine interesting sources that you found.
• Communication -  Correct citations helps you communicate effectively with potential peers within a discipline.
• Skills -  Correct citation demonstrates your research and documentation abilities to your professor.
• Avoid Plagiarism -  Correct citation use helps protect you from plagiarizing.

Note: a hyperlink or URL included in the text is not the same as a citation. Ex: "Higher gas prices are on the way (cnn.com/specialreport)." URLs in the text, while common on the internet, are not considered a correct form of scholarly citation.

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Citation generators are programs that can help you craft citations quickly and easily.  They are not as robust as full citation managers like Zotero and RefWorks, but can help make quick work of shorter bibliography needs.  Choose a citation style and enter the bibliographic details of the works consulted (author, title, publication date, etc.) to automatically create citations. 

It is important to note that you must enter data accurately and carefully check the automatically generated citations for errors.  As noted in the Purdue OWL's guide to Using Citation Generators Responsibly (linked below), " relying entirely on citation generators rather than on one’s judgment as a writer can lead to errors."

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Title: realm: reference resolution as language modeling.

Abstract: Reference resolution is an important problem, one that is essential to understand and successfully handle context of different kinds. This context includes both previous turns and context that pertains to non-conversational entities, such as entities on the user's screen or those running in the background. While LLMs have been shown to be extremely powerful for a variety of tasks, their use in reference resolution, particularly for non-conversational entities, remains underutilized. This paper demonstrates how LLMs can be used to create an extremely effective system to resolve references of various types, by showing how reference resolution can be converted into a language modeling problem, despite involving forms of entities like those on screen that are not traditionally conducive to being reduced to a text-only modality. We demonstrate large improvements over an existing system with similar functionality across different types of references, with our smallest model obtaining absolute gains of over 5% for on-screen references. We also benchmark against GPT-3.5 and GPT-4, with our smallest model achieving performance comparable to that of GPT-4, and our larger models substantially outperforming it.

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• Introduction
• Finding sources

Evaluating sources

• Integrating sources

Citing sources

Tools and resources, a quick guide to working with sources.

Working with sources is an important skill that you’ll need throughout your academic career.

It includes knowing how to find relevant sources, assessing their authority and credibility, and understanding how to integrate sources into your work with proper referencing.

This quick guide will help you get started!

Finding relevant sources

Sources commonly used in academic writing include academic journals, scholarly books, websites, newspapers, and encyclopedias. There are three main places to look for such sources:

• Research databases: Databases can be general or subject-specific. To get started, check out this list of databases by academic discipline . Another good starting point is Google Scholar .
• Your institution’s library: Use your library’s database to narrow down your search using keywords to find relevant articles, books, and newspapers matching your topic.
• Other online resources: Consult popular online sources like websites, blogs, or Wikipedia to find background information. Be sure to carefully evaluate the credibility of those online sources.

When using academic databases or search engines, you can use Boolean operators to refine your results.

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In academic writing, your sources should be credible, up to date, and relevant to your research topic. Useful approaches to evaluating sources include the CRAAP test and lateral reading.

CRAAP is an abbreviation that reminds you of a set of questions to ask yourself when evaluating information.

• Currency: Does the source reflect recent research?
• Relevance: Is the source related to your research topic?
• Authority: Is it a respected publication? Is the author an expert in their field?
• Accuracy: Does the source support its arguments and conclusions with evidence?
• Purpose: What is the author’s intention?

Lateral reading

Lateral reading means comparing your source to other sources. This allows you to:

• Verify evidence
• Contextualize information
• Find potential weaknesses

If a source is using methods or drawing conclusions that are incompatible with other research in its field, it may not be reliable.

Integrating sources into your work

Once you have found information that you want to include in your paper, signal phrases can help you to introduce it. Here are a few examples:

Following the signal phrase, you can choose to quote, paraphrase or summarize the source.

• Quoting : This means including the exact words of another source in your paper. The quoted text must be enclosed in quotation marks or (for longer quotes) presented as a block quote . Quote a source when the meaning is difficult to convey in different words or when you want to analyze the language itself.
• Paraphrasing : This means putting another person’s ideas into your own words. It allows you to integrate sources more smoothly into your text, maintaining a consistent voice. It also shows that you have understood the meaning of the source.
• Summarizing : This means giving an overview of the essential points of a source. Summaries should be much shorter than the original text. You should describe the key points in your own words and not quote from the original text.

Whenever you quote, paraphrase, or summarize a source, you must include a citation crediting the original author.

Citing your sources is important because it:

• Allows you to avoid plagiarism
• Establishes the credentials of your sources
• Backs up your arguments with evidence
• Allows your reader to verify the legitimacy of your conclusions

The most common citation styles are APA, MLA, and Chicago style. Each citation style has specific rules for formatting citations.

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Scribbr offers tons of tools and resources to make working with sources easier and faster. Take a look at our top picks:

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This paper is in the following e-collection/theme issue:

Published on 4.4.2024 in Vol 26 (2024)

Moving Biosurveillance Beyond Coded Data Using AI for Symptom Detection From Physician Notes: Retrospective Cohort Study

Authors of this article:

Original Paper

• Andrew J McMurry 1, 2 , PhD   ; 
• Amy R Zipursky 1, 3 , MD, MBI   ; 
• Alon Geva 1, 4, 5 , MD, MPH   ; 
• Karen L Olson 1, 2 , PhD   ; 
• James R Jones 1 , MPhil   ; 
• Vladimir Ignatov 1 , MFA   ; 
• Timothy A Miller 1, 2 , PhD   ; 
• Kenneth D Mandl 1, 2, 6 , MD, MPH  

1 Computational Health Informatics Program, Boston Children's Hospital, Boston, MA, United States

2 Department of Pediatrics, Harvard Medical School, Boston, MA, United States

3 Division of Pediatric Emergency Medicine, Department of Pediatrics, The Hospital for Sick Children, Toronto, ON, Canada

4 Division of Critical Care Medicine, Department of Anesthesiology, Critical Care, and Pain Medicine, Boston Children's Hospital, Boston, MA, United States

5 Department of Anaesthesia, Harvard Medical School, Boston, MA, United States

6 Department of Biomedical Informatics, Harvard Medical School, Boston, MA, United States

Corresponding Author:

Kenneth D Mandl, MD, MPH

Computational Health Informatics Program

Boston Children's Hospital

Landmark 5506 Mail Stop BCH3187, 401 Park Drive

Boston, MA, 02215

United States

Phone: 1 6173554145

Email: [email protected]

Background: Real-time surveillance of emerging infectious diseases necessitates a dynamically evolving, computable case definition, which frequently incorporates symptom-related criteria. For symptom detection, both population health monitoring platforms and research initiatives primarily depend on structured data extracted from electronic health records.

Objective: This study sought to validate and test an artificial intelligence (AI)–based natural language processing (NLP) pipeline for detecting COVID-19 symptoms from physician notes in pediatric patients. We specifically study patients presenting to the emergency department (ED) who can be sentinel cases in an outbreak.

Methods: Subjects in this retrospective cohort study are patients who are 21 years of age and younger, who presented to a pediatric ED at a large academic children’s hospital between March 1, 2020, and May 31, 2022. The ED notes for all patients were processed with an NLP pipeline tuned to detect the mention of 11 COVID-19 symptoms based on Centers for Disease Control and Prevention (CDC) criteria. For a gold standard, 3 subject matter experts labeled 226 ED notes and had strong agreement ( F 1 -score=0.986; positive predictive value [PPV]=0.972; and sensitivity=1.0). F 1 -score, PPV, and sensitivity were used to compare the performance of both NLP and the International Classification of Diseases, 10th Revision (ICD-10) coding to the gold standard chart review. As a formative use case, variations in symptom patterns were measured across SARS-CoV-2 variant eras.

Results: There were 85,678 ED encounters during the study period, including 4% (n=3420) with patients with COVID-19. NLP was more accurate at identifying encounters with patients that had any of the COVID-19 symptoms ( F 1 -score=0.796) than ICD-10 codes ( F 1 -score =0.451). NLP accuracy was higher for positive symptoms (sensitivity=0.930) than ICD-10 (sensitivity=0.300). However, ICD-10 accuracy was higher for negative symptoms (specificity=0.994) than NLP (specificity=0.917). Congestion or runny nose showed the highest accuracy difference (NLP: F 1 -score=0.828 and ICD-10: F 1 -score=0.042). For encounters with patients with COVID-19, prevalence estimates of each NLP symptom differed across variant eras. Patients with COVID-19 were more likely to have each NLP symptom detected than patients without this disease. Effect sizes (odds ratios) varied across pandemic eras.

Conclusions: This study establishes the value of AI-based NLP as a highly effective tool for real-time COVID-19 symptom detection in pediatric patients, outperforming traditional ICD-10 methods. It also reveals the evolving nature of symptom prevalence across different virus variants, underscoring the need for dynamic, technology-driven approaches in infectious disease surveillance.

Introduction

Real-time emerging infection surveillance requires a case definition that often involves symptomatology. To detect symptoms, population health monitoring systems and research studies tend to largely rely on structured data from electronic health records, including the International Classification of Diseases, 10th Revision (ICD-10) codes [ 1 ]. However, symptoms are not diagnoses and, therefore, may not be consistently coded, leading to incorrect estimates of the prevalence of COVID-19 symptoms [ 2 ]. Natural language processing (NLP) of unstructured data from electronic health records has proven useful in recognizing COVID-19 symptoms and identifying additional signs and symptoms compared to structured data alone [ 3 , 4 ]. However, surveillance of COVID-19 symptoms is nuanced as symptoms have been shown to differ by variant eras [ 5 , 6 ] and by age, with pediatric patients generally experiencing milder symptoms [ 7 ]. For example, while loss of taste or smell was reported with early COVID-19 variants, it was less commonly reported during the Omicron wave and in younger patients who more frequently experience fever and cough [ 8 - 11 ]. Understanding symptom patterns in children during different COVID-19 variant eras is important. Early in the pandemic, the availability of molecular testing was extremely limited. The less severe course of infection and varying presentations may lead to under testing due to mild symptoms [ 12 ], potentially underestimating pediatric COVID-19 cases. Additionally, relatively asymptomatic children can still transmit the virus. Tailoring interventions based on age-specific manifestations contribute to effective control of virus transmission within communities.

We sought to validate and test an open-source artificial intelligence (AI)–based NLP pipeline that includes a large language model (LLM) to detect COVID-19 symptoms from physician notes. As a formative use case, we sought to illustrate how this pipeline could detect COVID-19 symptoms and differentiate symptom patterns across SARS-CoV-2 variant eras in pediatric patients. We specifically study patients presenting to the emergency department (ED) who can be sentinel cases in an outbreak.

Study Design and Setting

This was a retrospective cohort study of all patients up to 21 years of age presenting to the ED of a large, free-standing, university-affiliated, pediatric hospital between March 1, 2020, and May 31, 2022.

Ethical Considerations

The Boston Children’s Hospital Committee on Clinical Investigation performed ethical, privacy, and confidentiality reviews of the study and found it to be exempt from human subjects oversight. A waiver of consent was obtained to cover the targeted extraction and secure review of clinical notes by approved study personnel in protected environments within the hospital firewall.

Study Variables

The main dependent variables were a set of 11 COVID-19 symptoms based on Centers for Disease Control and Prevention (CDC) criteria [ 13 ]—fever or chills, cough, shortness of breath or difficulty breathing, fatigue, muscle or body aches, headache, new loss of taste or smell, sore throat, congestion or runny nose, nausea or vomiting, and diarrhea. We identified these symptoms by both NLP and ICD-10 codes. For the formative use case, the study period was divided into 3 variant eras defined using Massachusetts COVID-19 data from Covariant [ 14 ]. The pre-Delta era was from March 1, 2020, to June 20, 2021; the Delta era was from June 21, 2021, to December 19, 2021; and the Omicron era was from December 20, 2021, onward. A diagnosis of COVID-19 was defined as a positive SARS-CoV-2 polymerase chain reaction (PCR) test or the presence of ICD-10 code U07.1 for COVID-19 during the same ED encounter in which symptoms were evaluated.

AI/NLP Pipeline Development

A total of 3 reviewers reached a consensus on a symptom concept dictionary [ 15 ] to capture each of the 11 COVID-19 symptoms. They relied on the Unified Medical Language System [ 16 ], which has a nearly comprehensive list of symptom descriptors [ 17 ], including SNOMED (SNOMED International) coded clinical terms [ 18 ], ICD-10 codes for administrative billing, abbreviations, and common language for patients [ 19 ]. The open-source and free Apache cTAKES (Apache Software Foundation) NLP pipeline was tuned to recognize and extract coded concepts for positive symptom mentions (based on the dictionary) from physician notes [ 20 ]. Apache cTAKES uses a NegEx algorithm which can help address negation [ 20 - 23 ]. To further address negation, we incorporated an LLM, Bidirectional Encoder Representations from Transformers, that was fine-tuned for negation classification on clinical text [ 24 , 25 ].

Gold Standard

A total of 2 reviewers established a gold standard by manually reviewing physician ED notes. After all notes were labeled by the cTAKES pipeline, a test set of 226 ED notes was loaded into Label Studio [ 26 ], an open-source application for ground truth labeling. These notes were from patients both with and without COVID-19 and were selected to ensure that each of the 11 symptoms was mentioned in at least 30 ED notes. Some notes mentioned more than 1 symptom. Using an annotation guide ( Multimedia Appendix 1 ), 2 reviewers, who were masked from the terms identified by the NLP pipeline for note selection, each labeled 113 notes for mention of the 11 COVID-19 symptoms. As per the guide, only symptoms relevant to the present illness were considered positive mentions. Symptoms were not considered positive mentions if stated as past medical history, family history, social history, or an indication for a medication unrelated to the encounter.

Interrater Reliability

The F 1 -score was used to assess consistency in manual chart review. The F 1 -score is the balance of sensitivity and positive predictive value (PPV) [ 27 ]. It was computed by comparing the annotations of each of the 2 initial reviewers to those of a third reviewer, who independently labeled a subset (56/226, 25%) of notes annotated by the other reviewers. The choice of F 1 -score as the metric for agreement was informed by the observed high frequency of true negative annotations when they were assigned by chance [ 20 , 27 , 28 ]. Reliability analyses used Python (version 3.10; Python Software Foundation).

AI/NLP and ICD-10 Accuracy

Accuracy measures of the true symptom percentages in the test set for each symptom included F 1 -score, PPV, sensitivity, and specificity [ 29 , 30 ].

Formative Use Case

The impact of pandemic variant era on COVID-19 symptomatology was examined. Descriptive statistics were used to characterize patients presenting to the ED during each pandemic era. The percentage of patients in the ED with symptoms of COVID-19 was assessed in separate analyses for each symptom using chi-square analyses of 3×2 tables (pandemic era × symptom presence or absence) with α set at .05. Post hoc chi-square tests were used to compare each pandemic era with all others using a Bonferroni adjusted α of .017. To assess the effect of pandemic era, COVID-19 status, and the interaction of these variables on whether or not a patient had each symptom, logistic regression was used in separate analyses for each symptom. Bonferroni adjusted confidence limits were used for post hoc analyses. If the interaction term was not significant, the main effects of COVID-19 and variant era were reported. Data were analyzed using SAS (version 9.4; SAS Institute Inc).

Study Population

There were 59,173 unique patients with 85,678 ED encounters during the study period. For each ED encounter, there was 1 final physician ED note that aggregated all ED physician documentation. Characteristics of the entire study cohort and variant-specific cohorts are summarized in Table 1 . A patient could appear in the cohort more than once if they had multiple ED encounters.

a PCR: polymerase chain reaction.

b ICD-10: International Classification of Diseases, 10th Revision.

High consistency was demonstrated between reviewer 3, who labeled a subset of notes, and both reviewers 1 and 2, who each labeled half of the notes chosen to establish the gold standard. The F 1 -scores for the 2 reviewers were 0.988 and 0.984, respectively. The PPV was 0.976 and 0.968 and sensitivity was 1.0 for both.

AI or NLP ICD-10 Accuracy

As shown in Table 2 , the F 1 -score for NLP was higher and thus more accurate at identifying encounters in the test set with patients that had any of the COVID-19 symptoms than ICD-10. NLP also had higher F 1 -score for each individual symptom. In addition, NLP sensitivity of true positive symptoms was higher than ICD-10. However, NLP accuracy of true negative symptoms (specificity) was somewhat lower compared to ICD-10.

a NLP: natural language processing.

c F 1 -score: accuracy measure balancing PPV and sensitivity.

d PPV: positive predictive value.

The 2 most prevalent symptoms, cough and fever, had sensitivity scores for NLP that were among the highest of the symptoms, and much higher than those for ICD-10 codes. The greatest discrepancy between NLP and ICD-10 F 1 -scores was for congestion or runny nose. The smallest difference was for diarrhea.

Prevalence of Symptoms Over Time

The percentage of ED encounters with patients with COVID-19 who had symptoms was estimated using the NLP pipeline and ICD-10 codes. As shown in Figure 1 , during each month of the study, the percentage of encounters with no symptoms detected was much lower using NLP compared to ICD-10. Using NLP, the range was from 0% to 19% of encounters (mean 6%, SD 4%), while with ICD-10, the range was 22% to 52% (mean 38%, SD 7%).

The percentage of encounters with patients with COVID-19 who presented with each symptom by month was higher using NLP than ICD-10 ( Multimedia Appendix 2 ). The 2 most common symptoms, cough and fever, are shown in Figures 2 and 3 . On average, cough was identified during 52% (SD 13%) of the encounters each month using NLP, but only 15% (SD 5%) using ICD-10. On average, fever characterized 70% (SD 11%) of encounters using NLP, but 41% (SD 9%) using ICD-10.

Using ICD-10, there were many months where individual symptoms were not detected. Of the 27 study months, loss of taste or smell was not detected using ICD-10 during 24 months, nor were muscle or body aches during 13 months. A total of 3 more symptoms had at least 3 consecutive months where each was not detected using ICD-10. These were congestion or runny nose (9 total months, not all consecutive), sore throat (8 months), and fatigue (7 months). Sporadic months without detection using ICD-10 were observed for headache (5 months), diarrhea (2 months), cough (1 month), and nausea or vomiting (1 month). Using NLP, sporadic months without detection were observed for just 2 symptoms, loss of taste or smell (6 months) and sore throat (2 months).

Prevalence of Symptoms Across Variant Eras

The prevalence estimates of symptoms across variant eras for encounters with patients with COVID-19 differed for each symptom identified by NLP, except for nausea or vomiting and sore throat ( Table 3 ). Post hoc analyses revealed several patterns. New loss of taste or smell was the only symptom that varied across all 3 eras. It was most common in the pre-Delta era, followed by the Delta era, and then the Omicron era. Congestion or runny nose, cough, and fever or chills were more common during the Delta and Omicron era than during the pre-Delta era, but the Delta era did not differ from the Omicron era. Muscle or body aches were more common during the pre-Delta era than both the Delta and Omicron eras, but the Delta era did not differ from the Omicron era. Diarrhea, fatigue, headache, and shortness of breath were more common during the pre-Delta era than the Omicron era but were not different than the Delta era, and the Delta era did not differ from the Omicron era. Nausea or vomiting and sore throat did not differ by variant era. The chi-square results are in Multimedia Appendix 3 .

a,b,c Variant eras with the same superscript across a row did not differ in post hoc analyses.

Symptoms by COVID-19 Status and Variant Era

The interaction of COVID-19 status and variant era on the presence of each symptom is shown in Table 4 . However, because the interaction was not significant for 2 symptoms, fever and chills, and sore throat, the main effects for COVID-19 status are shown for both ( P <.001). The odds ratios (ORs) indicate that patients with COVID-19 were more likely to have each of these 2 symptoms than patients without this disease. These symptoms were also more likely to occur during the Delta and Omicron era than during the pre-Delta era. For the remaining symptoms, the interaction term was significant and the ORs in each variant era are shown in the table. The ORs comparing patients with COVID-19 to those without the disease differed among the variant eras. Several patterns were observed. Patients with COVID-19 were more likely to exhibit each of the symptoms of congestion or runny nose, cough, fatigue, headache, muscle or body aches, new loss of taste or smell, or shortness of breath or difficulty breathing. However, effect sizes (ORs) differed among pandemic eras. For diarrhea, this symptom was more likely for patients with COVID-19 in the pre-Delta and Delta eras, but not during the Omicron era. And nausea was more likely only in the pre-Delta era. Significant ORs ranged in size from 1.3 to 26.7 (mean 4.6, SD 5.3). The logistic regression results are in Multimedia Appendix 4 .

a Odds ratios compare patients with COVID-19 at an ED encounter to patients without the disease.

b CL: Bonferroni adjusted confidence limits in post hoc analyses.

c If the interaction term was significant, the effect of COVID-19 during each variant era is shown. Otherwise, the effect for COVID-19 is shown.

d Type 3 test of the interaction term (variant era × COVID-19) in a logistic regression analysis.

Principal Findings

We find evidence that AI-based NLP of physician notes is a superior method for capturing patient symptoms for real-time biosurveillance than reliance on traditional approaches using ICD-10. NLP was more sensitive than ICD-10 codes in identifying symptoms and some symptoms could only be detected using NLP. As a form of internal validation, the symptoms identified by the CDC as associated with COVID-19 were more common in patients with than without this disease.

Comparison With Prior Work

The study was also able to capture a nuanced picture of symptom prevalence and odds across different SARS-CoV-2 variant eras. Consistent with previous literature, symptom patterns changed over time as new variants emerged. Variants may present with differences in symptomatology as a result of a number of factors including differences in mutations in spike proteins, receptor binding, and ability to escape host antibodies [ 31 ]. As has been previously reported [ 11 , 32 - 35 ], we found that fever or chills were the most common COVID-19 symptom across the variants. In our cohort, shortness of breath was less common during the Omicron era than during the pre-Delta era. The Omicron variant has less of an ability to replicate in the lungs compared to the bronchi, which may explain why this symptom became less common [ 36 ]. Studies have reported sore throat as a common symptom in the Omicron era, but we did not observe a significant difference across eras [ 8 , 9 ]. It is possible that we did not see a higher percentage of sore throats in the Omicron era because it may be more challenging for pediatric patients to describe this symptom. One study found that sore throat was observed more often in those of 5-20 years of age compared to those of 0-4 years of age [ 8 ]. Similarly, a study reported that sore throat was more common in those greater than or equal to 13 years of age in the Omicron era compared to the Delta era [ 37 ]. In our study cohort, approximately half of the patients were younger than 5 years of age. As children this age may not be able to describe their symptoms well, symptoms that are also signs, such as fever or cough, might be more commonly documented in physician notes than symptoms such as sore throat. New loss of taste or smell was most common in the pre-Delta era, followed by the Delta era and then the Omicron era in this study. This symptom has been reported less commonly in the Omicron era [ 8 , 9 ]. Studies have postulated that patients with the Omicron variant are less likely to present with loss of taste or smell as this variant has less penetration of the mucus layer and therefore, may be less likely to infect the olfactory epithelium [ 38 ].

Limitations

There were important limitations in our use of NLP. The NLP pipeline was tested with a set of notes where some symptoms were more frequent in the test set (eg, loss of taste or smell) than in the formative use case. This was done to have sufficient data to evaluate the symptom pipeline. The NLP pipeline does not account for vital signs and so fever may not have been detected with the pipeline if it was documented in a patient’s vital signs rather than the clinical text. The cTAKES tool in the pipeline lacks the temporal context to ascertain if the mention of a symptom in a note is a new symptom or a prior symptom. We modified our technique because of this but nevertheless may have overestimated the prevalence of symptoms in our study. Future work will involve filtering by note section so that certain components of a note like past medical history are not included. We used 2 techniques to recognize negation, but some negated symptoms (eg, “patient had no cough”) were still captured as positive symptom mentions leading to a possible overestimation of symptom prevalence. Finally, this NLP pipeline did involve substantial preprocessing. We plan to evaluate the implementation of Generative Pre-trained Transformer (GPT) for this task. GPT-4 was able to extract COVID-19 symptoms in a recent study [ 39 ] and it may limit the need for preprocessing.

Our formative study had some limitations. First, we examined COVID-19 symptoms in patients presenting to a single urban pediatric ED. Patients presenting to outpatient settings, who likely had milder symptoms, were not included and our results may reflect patients with more severe symptoms. And because the setting was a single site, results may not generalize to other EDs. Second, we defined COVID-19 status as positive if a patient had a PCR positive test for COVID-19 or an appropriate ICD-10 code at the ED encounter. Patients who were COVID-19 positive on a test at home or at an outside center may not have been captured by this definition even if they presented to the ED with COVID-19 [ 40 ]. Additionally, symptoms may have differed across variant eras as a result of COVID-19 vaccinations or previous infections rather than variant differences. Literature in adults shows that vaccination is associated with a decrease in systemic symptoms [ 41 ]. The United States Food and Drug Administration authorized the use of the COVID-19 vaccine in October 2021, during the Delta era and prior to the Omicron era, for children 5-11 years of age [ 42 ]. Vaccination rates for pediatric patients vary by age group in Massachusetts, as of April 3, 2023, of those 0-19 years of age, 3% to 57% have received a primary series but have not been boosted, and 3% to 18% have been boosted since September 1, 2022 [ 43 ]. As such, some patients in the Delta and Omicron eras may have been vaccinated or had previous COVID-19 infections [ 44 ].

Conclusions

In an era where rapid and accurate infectious disease surveillance is crucial, this study underscores the transformative potential of AI-based NLP for real-time symptom detection, significantly outperforming traditional methods such as ICD-10 coding. The dynamic adaptability of NLP technology allows for the nuanced capture of evolving symptomatology across different virus variants, offering a more responsive and precise tool kit for biosurveillance efforts. Its integration into existing health care infrastructure could be a game changer, elevating our capabilities to monitor, understand, and ultimately control the spread of emerging infectious diseases.

Acknowledgments

This study was supported by the Centers for Disease Control and Prevention (CDC) of the US Department of Health and Human Services (HHS) as part of a financial assistance award. The contents are those of the authors and do not necessarily represent the official views of, nor an endorsement by CDC, HHS, or the US Government. Support was also obtained from the National Center for Advancing Translational Sciences, National Institutes of Health Cooperative Agreement (U01TR002623). ARZ was supported by a training grant from the National Institute of Child Health and Human Development (T32HD040128). Generative artificial intelligence (AI) was not used to design or conduct this study.

Data Availability

All data analyzed during this study for the formative use case are in Multimedia Appendix 5 of this published article.

Authors' Contributions

KDM, AJM, and TAM contributed to the conceptualization. KDM contributed to the funding. AJM, ARZ, AG, and KLO performed the formal analysis. AJM, JRJ, and VI contributed to the software. AJM, ARZ, and KDM contributed to writing original drafts. KLO and AG contributed to writing review and edits.

Conflicts of Interest

TAM is a member of the advisory council for Lavita AI. Others declare no conflicts of interest.

COVID-19 symptoms annotation guide.

Detection of COVID-19 symptoms using NLP and ICD-10 by month for emergency department encounters with patients with COVID-19. ICD-10: International Classification of Diseases, 10th Revision; NLP: natural language processing.

The chi-square analysis of COVID-19 symptom prevalence by pandemic variant era for emergency department encounters with patients with COVID-19, symptoms were detected using NLP. NLP: natural language processing.

Logistic regression analysis of the effect of COVID-19 status, pandemic variant era, and their interaction on symptom status for ED encounters, symptoms were detected using NLP. ED: emergency department; NLP: natural language processing.

Data files for the time series figures, the chi-square analysis of symptom prevalence, and the logistic regression analysis of the effects of COVID-19 status and pandemic variant era on symptom status.

• Subramanian A, Nirantharakumar K, Hughes S, Myles P, Williams T, Gokhale KM, et al. Symptoms and risk factors for long COVID in non-hospitalized adults. Nat Med. 2022;28(8):1706-1714. [ FREE Full text ] [ CrossRef ] [ Medline ]
• Crabb BT, Lyons A, Bale M, Martin V, Berger B, Mann S, et al. Comparison of International Classification of Diseases and Related Health Problems, Tenth Revision codes with electronic medical records among patients with symptoms of coronavirus disease 2019. JAMA Netw Open. 2020;3(8):e2017703. [ FREE Full text ] [ CrossRef ] [ Medline ]
• Wang J, Abu-El-Rub N, Gray J, Pham HA, Zhou Y, Manion FJ, et al. COVID-19 SignSym: a fast adaptation of a general clinical NLP tool to identify and normalize COVID-19 signs and symptoms to OMOP common data model. J Am Med Inform Assoc. 2021;28(6):1275-1283. [ FREE Full text ] [ CrossRef ] [ Medline ]
• Malden DE, Tartof SY, Ackerson BK, Hong V, Skarbinski J, Yau V, et al. Natural language processing for improved characterization of COVID-19 symptoms: observational study of 350,000 patients in a large integrated health care system. JMIR Public Health Surveill. 2022;8(12):e41529. [ FREE Full text ] [ CrossRef ] [ Medline ]
• Di Chiara C, Boracchini R, Sturniolo G, Barbieri A, Costenaro P, Cozzani S, et al. Clinical features of COVID-19 in Italian outpatient children and adolescents during parental, Delta, and Omicron waves: a prospective, observational, cohort study. Front Pediatr. 2023;11:1193857. [ FREE Full text ] [ CrossRef ] [ Medline ]
• Sumner MW, Xie J, Zemek R, Winston K, Freire G, Burstein B, et al. Comparison of symptoms associated with SARS-CoV-2 variants among children in Canada. JAMA Netw Open. 2023;6(3):e232328. [ FREE Full text ] [ CrossRef ] [ Medline ]
• Liguoro I, Pilotto C, Bonanni M, Ferrari ME, Pusiol A, Nocerino A, et al. SARS-COV-2 infection in children and newborns: a systematic review. Eur J Pediatr. 2020;179(7):1029-1046. [ FREE Full text ] [ CrossRef ] [ Medline ]
• Menni C, Valdes AM, Polidori L, Antonelli M, Penamakuri S, Nogal A, et al. Symptom prevalence, duration, and risk of hospital admission in individuals infected with SARS-CoV-2 during periods of Omicron and Delta variant dominance: a prospective observational study from the ZOE COVID Study. Lancet. 2022;399(10335):1618-1624. [ FREE Full text ] [ CrossRef ] [ Medline ]
• Akaishi T, Kushimoto S, Katori Y, Sugawara N, Egusa H, Igarashi K, et al. COVID-19-related symptoms during the SARS-CoV-2 Omicron (B.1.1.529) variant surge in Japan. Tohoku J Exp Med. 2022;258(2):103-110. [ FREE Full text ] [ CrossRef ] [ Medline ]
• García-Vera C, Castejón-Ramírez S, Miranda EL, Abadía RH, Ventura MG, Navarro EB, et al. COVID-19 in children: clinical and epidemiological spectrum in the community. Eur J Pediatr. 2022;181(3):1235-1242. [ FREE Full text ] [ CrossRef ] [ Medline ]
• Viner RM, Ward JL, Hudson LD, Ashe M, Patel SV, Hargreaves D, et al. Systematic review of reviews of symptoms and signs of COVID-19 in children and adolescents. Arch Dis Child. 2021;106:802-807. [ FREE Full text ] [ CrossRef ] [ Medline ]
• COVID-19 disease in children and adolescents: scientific brief, 29 September 2021. World Health Organization. 2021. URL: https:/​/www.​who.int/​publications/​i/​item/​WHO-2019-nCoV-Sci_Brief-Children_and_adolescents-2021.​1?ssp=1&setlang=en&cc=US [accessed 2024-02-28]
• Symptoms of COVID-19. Centers for Disease Control and Prevention. 2022. URL: https://www.cdc.gov/coronavirus/2019-ncov/symptoms-testing/symptoms.html [accessed 2024-02-28]
• Hodcroft E. CoVariants. CoVariants. 2021. URL: https://covariants.org/ [accessed 2024-02-28]
• Machine-learning-for-medical-language / ctakes-client-py. Github. URL: https:/​/github.​com/​Machine-Learning-for-Medical-Language/​ctakes-client-py/​blob/​main/​ctakesclient/​resources/​covid_symptoms.​bsv [accessed 2024-02-28]
• Bodenreider O. The Unified Medical Language System (UMLS): integrating biomedical terminology. Nucleic Acids Res. 2004;32(Database issue):D267-D270. [ FREE Full text ] [ CrossRef ] [ Medline ]
• Köhler S, Gargano M, Matentzoglu N, Carmody LC, Lewis-Smith D, Vasilevsky NA, et al. The human phenotype ontology in 2021. Nucleic Acids Res. 2021;49(D1):D1207-D1217. [ FREE Full text ] [ CrossRef ] [ Medline ]
• SNOMEDCT_US (SNOMED CT, US edition)—synopsis, UMLS vocabularies. Unified Medical Language System (UMLS). URL: https://www.nlm.nih.gov/research/umls/sourcereleasedocs/current/SNOMEDCT_US/index.html [accessed 2024-02-28]
• CHV (Consumer Health Vocabulary)—synopsis, UMLS vocabularies. Unified Medical Language System (UMLS). URL: https://www.nlm.nih.gov/research/umls/sourcereleasedocs/current/CHV/index.html [accessed 2024-02-28]
• Savova GK, Masanz JJ, Ogren PV, Zheng J, Sohn S, Kipper-Schuler KC, et al. Mayo clinical Text Analysis and Knowledge Extraction System (cTAKES): architecture, component evaluation and applications. J Am Med Inform Assoc. 2010;17(5):507-513. [ FREE Full text ] [ CrossRef ] [ Medline ]
• Chapman WW, Bridewell W, Hanbury P, Cooper GF, Buchanan BG. A simple algorithm for identifying negated findings and diseases in discharge summaries. J Biomed Inform. 2001;34(5):301-310. [ FREE Full text ] [ CrossRef ] [ Medline ]
• Harkema H, Dowling JN, Thornblade T, Chapman WW. ConText: an algorithm for determining negation, experiencer, and temporal status from clinical reports. J Biomed Inform. 2009;42(5):839-851. [ FREE Full text ] [ CrossRef ] [ Medline ]
• Chapman WW, Hillert D, Velupillai S, Kvist M, Skeppstedt M, Chapman BE, et al. Extending the NegEx lexicon for multiple languages. Stud Health Technol Inform. 2013;192:677-681. [ FREE Full text ] [ Medline ]
• Machine-learning-for-medical-language. GitHub. URL: https://github.com/Machine-Learning-for-Medical-Language [accessed 2024-02-28]
• Miller T, Bethard S, Amiri H, Savova G. Unsupervised domain adaptation for clinical negation detection. 2017. Presented at: BioNLP; August 4, 2017;165-170; Vancouver, Canada. URL: https://aclanthology.org/W17-2320/ [ CrossRef ]
• Tkachenko M, Malyuk M, Holmanyuk A, Liubimov N. Label studio: data labeling software. GitHub. 2020. URL: https://github.com/heartexlabs/label-studio [accessed 2024-02-28]
• Hripcsak G, Rothschild AS. Agreement, the f-measure, and reliability in information retrieval. J Am Med Inform Assoc. 2005;12(3):296-298. [ FREE Full text ] [ CrossRef ] [ Medline ]
• McHugh ML. Interrater reliability: the kappa statistic. Biochem Med (Zagreb). 2012;22(3):276-282. [ FREE Full text ] [ Medline ]
• Habibzadeh F, Habibzadeh P, Yadollahie M. The apparent prevalence, the true prevalence. Biochem Med (Zagreb). 2022;32(2):020101. [ FREE Full text ] [ CrossRef ] [ Medline ]
• Monaghan TF, Rahman SN, Agudelo CW, Wein AJ, Lazar JM, Everaert K, et al. Foundational statistical principles in medical research: sensitivity, specificity, positive predictive value, and negative predictive value. Medicina (Kaunas). 2021;57(5):503. [ FREE Full text ] [ CrossRef ] [ Medline ]
• Lauring AS, Hodcroft EB. Genetic variants of SARS-CoV-2-what do they mean? JAMA. 2021;325(6):529-531. [ FREE Full text ] [ CrossRef ] [ Medline ]
• Götzinger F, Santiago-García B, Noguera-Julián A, Lanaspa M, Lancella L, Carducci FIC, et al. COVID-19 in children and adolescents in Europe: a multinational, multicentre cohort study. Lancet Child Adolesc Health. 2020;4(9):653-661. [ FREE Full text ] [ CrossRef ] [ Medline ]
• King JA, Whitten TA, Bakal JA, McAlister FA. Symptoms associated with a positive result for a swab for SARS-CoV-2 infection among children in Alberta. CMAJ. 2021;193(1):E1-E9. [ FREE Full text ] [ CrossRef ] [ Medline ]
• Takács AT, Bukva M, Gavallér G, Kapus K, Rózsa M, Bán-Gagyi B, et al. Epidemiology and clinical features of SARS-CoV-2 infection in hospitalized children across four waves in Hungary: a retrospective, comparative study from march 2020 to december 2021. Health Sci Rep. 2022;5(6):e937. [ FREE Full text ] [ CrossRef ] [ Medline ]
• Kenney PO, Chang AJ, Krabill L, Hicar MD. Decreased clinical severity of pediatric acute COVID-19 and MIS-C and increase of incidental cases during the Omicron wave in comparison to the Delta wave. Viruses. 2023;15(1):180. [ FREE Full text ] [ CrossRef ] [ Medline ]
• Hui KPY, Ho JCW, Cheung MC, Ng KC, Ching RHH, Lai KL, et al. SARS-CoV-2 Omicron variant replication in human bronchus and lung ex vivo. Nature. 2022;603(7902):715-720. [ FREE Full text ] [ CrossRef ] [ Medline ]
• Shoji K, Akiyama T, Tsuzuki S, Matsunaga N, Asai Y, Suzuki S, et al. Clinical characteristics of COVID-19 in hospitalized children during the Omicron variant predominant period. J Infect Chemother. 2022;28(11):1531-1535. [ FREE Full text ] [ CrossRef ] [ Medline ]
• Butowt R, Bilińska K, von Bartheld C. Why does the Omicron variant largely spare olfactory function? implications for the pathogenesis of anosmia in coronavirus disease 2019. J Infect Dis. 2022;226(8):1304-1308. [ FREE Full text ] [ CrossRef ] [ Medline ]
• Wei WI, Leung CLK, Tang A, McNeil EB, Wong SYS, Kwok KO. Extracting symptoms from free-text responses using ChatGPT among COVID-19 cases in Hong Kong. Clin Microbiol Infect. 2024;30(1):142.e1-142.e3. [ FREE Full text ] [ CrossRef ] [ Medline ]
• Wang L, Zipursky AR, Geva A, McMurry AJ, Mandl KD, Miller TA. A computable case definition for patients with SARS-CoV2 testing that occurred outside the hospital. JAMIA Open. 2023;6(3):ooad047. [ FREE Full text ] [ CrossRef ] [ Medline ]
• Bramante CT, Proper JL, Boulware DR, Karger AB, Murray T, Rao V, et al. Vaccination against SARS-CoV-2 is associated with a lower viral load and likelihood of systemic symptoms. Open Forum Infect Dis. 2022;9(5):ofac066. [ FREE Full text ] [ CrossRef ] [ Medline ]
• FDA authorizes Pfizer-BioNTech COVID-19 vaccine for emergency use in children 5 through 11 years of age. U.S. Food and Drug Administration. 2021. URL: https:/​/www.​fda.gov/​news-events/​press-announcements/​fda-authorizes-pfizer-biontech-covid-19-vaccine-emergency-use-children-5-through-11-years-age [accessed 2024-02-28]
• Weekly COVID-19 vaccination report (as of April 3, 2023). Massachusetts Department of Public Health. URL: https://www.mass.gov/doc/weekly-covid-19-vaccination-report-april-5-2023/download [accessed 2024-02-28]
• Bhattacharyya RP, Hanage WP. Challenges in inferring intrinsic severity of the SARS-CoV-2 Omicron variant. N Engl J Med. 2022;386(7):e14. [ FREE Full text ] [ CrossRef ] [ Medline ]

Abbreviations

Edited by T de Azevedo Cardoso; submitted 06.10.23; peer-reviewed by D Liebovitz; comments to author 09.11.23; revised version received 30.11.23; accepted 27.02.24; published 04.04.24.

©Andrew J McMurry, Amy R Zipursky, Alon Geva, Karen L Olson, James R Jones, Vladimir Ignatov, Timothy A Miller, Kenneth D Mandl. Originally published in the Journal of Medical Internet Research (https://www.jmir.org), 04.04.2024.

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