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AMA Style (11th ed): Citing Your Sources

11th edition (2020) AMA style

In-text citations: basics

In the document/paper/poster you are writing, materials are cited using superscript numerals. The first reference used in a written document is listed as 1 in the reference list, and a 1 is inserted into the document immediately next to the fact, concept, or quotation being cited. Try to avoid placing multiple citation numbers at the end of a sentence. It is better practice to place the citation number next to the idea being cited, as this allows the reader to find the exact information in the source.

If the same reference is used multiple times in one document, use the same number to refer to it throughout the document.

At the end of the document, include a reference list with full citations to each item. Order citations as they appear in your paper.

You may also use author names in your writing, as long as these mentions are accompanied by numbered citations. For materials with one or two authors, include both names. For materials with 3 or more authors, include the first author's name and then et al. 


Finding treatments for breast cancer is a major goal for scientists.1,2 Some classes of drugs show more promise than others. Gradishar evaluated taxanes as a class.3 Other scientists have investigated individual drugs within this class, including Andre and Zielinski 2 and Joensuu and Gligorov. 4 Mita et al's investigation of cabazitaxel 5 seems to indicate a new role for this class of drugs.


Reference list:

1. Cancer Research Funding. National Cancer Institute. Publication date unavailable. Updated June 6, 2011. Accessed November 3, 2012.

2. Andre F, Zielinski CC. Optimal strategies for the treatment of metastatic triple-negative breast cancer with currently approved agents. Ann Oncol. 2012;23(Suppl 2):vi46-vi51.

3. Gradishar WJ. Taxanes for the treatment of metastatic breast cancer. Breast Cancer (Auckl.). 2012;6:159-171.

4. Joensuu H, Gligorov J. Adjuvant treatments for triple-negative breast cancers. Ann Oncol. 2012;Suppl 6:vi40-45.

5. Mita AC, Figlin R, Mita MM. Cabazitaxel: more than a new taxane for metastatic castrate-resistant prostate cancer? Clin Cancer Res. 2012;18(24):OF1-OF6.

Artificial Intelligence (A.I.)

"Nonhuman artificial intelligence, language models, machine learning, or similar technologies cannot be listed as authors because these technologies do not qualify for authorship." (quotation from AMA Manual, section 5.1.12). No AI programs should ever appear in the numbered reference list. AMA suggests that writers place an acknowledgement into the acknowledgement section of the manuscript or describe how AI was used in the Methods section of the manuscript. This advice is difficult to put into place in coursework, where assignments typically do not include either an acknowledgements or Methods section. When writing for a class, review  the syllabus or  speak with the faculty member to determine if you are allowed to use AI tools, then use this guide to get ideas for how to acknowledge the source.

"Section Acknowledgment of Use of Artificial Intelligence and Language Models in Writing and Editing

Authors should report the use of artificial intelligence, language models, machine learning, or similar technologies to create content or assist with writing or editing of manuscripts in the Acknowledgment section or the Methods section if this is part of formal research design or methods. This should include a description of the content that was created or edited and the name of the language model or tool, version and extension numbers, and manufacturer. (Note: this does not include basic tools for checking grammar, spelling, references, etc.)."

Strict interpretation of this for publication in a journal:

In 1-5 sentences, describe what you used AI to do in the manuscript, with enough information to explain the actual model used. Place this in the Methods section if the AI content was important to the methods. Otherwise, place in the Acknowledgements section. The AMA Manual does not provide any examples. Here are two examples created by a USC librarian that attempt to fulfill the AMA rules:

"On August 3, 2023, I used AI to summarize five research papers, to help me determine which idea was least studied and focus my topics for this essay. I used ChatGPT, model 3.5, made by OpenAI, hosted at"

"I used Bard, release 2023.07.13, made by Google and hosted at, to edit my manuscript. I uploaded my original writing and asked Bard to reduce the word count and make the language more formal. I also used Bard to determine which of the data points I had collected would be the most useful for including as figures, and used its advice to create figure 1 and table 2."

Potential ways to acknowledge use of AI tools in a written document for a course:

There is no guidance on this from the AMA Manual. As typical with this style, when no guidance exists, try to follow the basic rules of the style while respecting the underlying goal of any citation system: to acknowledge the use of other's ideas, thoughts, and opinions. While AI might not be a person, it’s still not you, so its ideas and work needs to be acknowledged. Based  on this, here are some options that might work:

- While your assignment may not require you to include a formal Methods section, you could decide to include one anyway. You could describe all the methods used to create this assignment: searching for literature, using modeling software, collaboratively editing with a colleague, etc., alongside how you used AI, and which model you used.

- Add a few sentences about your use of AI and the model (as recommended by AMA) into another section of the assignment. If you used AI to generate ideas, perhaps this acknowledge would fit into the introduction. If you used AI to edit the paper, this might be acknowledged in the conclusion. 

- AMA style requires a numbered reference list. You could add an unnumbered bullet point to the start or end of your reference list that acknowledges the use(s) of AI in your assignment and provides the model number as instructed by AMA.

Where do I put the numbers?

Within the text in AMA Citation Style, references are numbered and the numbers are shown in superscript.

Reference numbers should appear:

  • After the fact, quotation, or idea being cited
  • Outside periods and commas
  • Inside colons and semi-colons

If citing more than one reference at the same point, separate the numbers with commas and no spaces between.


  • This drug is used to treat hepatitis. 1
  • Storing latex at high heat may cause degradation, 2,3 but it is difficult to keep materials cool in a desert environment.
  • Some physicians choose to store prescription pads in locked cabinets 4; others keep them in their coats at all times. 5

How do I add numeric citations without using citation management software?

Citing and Writing handouts, AMA 11th