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National Library of Medicine Citation Style: In-Text Citations

This guide explains and shows examples of how to cite varied resources in the NLM style

Scholarly Papers

General Rules for In-Text Citations

  • Do not list a reference that you have not seen 1   

  • Cite only directly pertinent references.

  • Identify methods, procedures and equipment in sufficient detail to allow for reproducibility of results. For specific equipment, give the manufacturer's name and address in parentheses.2  

  • Provide references and brief descriptions for methods that have been published but are not well-known. Give reasons for using them and evaluate their limitations.2

  • In-text citations are in the format of a number in superscript. Example: …a recent study shows a decline in prevalence.17   
    To format superscript in MS Word for Windows: type the number in normal font, highlight it, right click and then check the box “Superscript.”
  • Assign a number to the reference when it is cited. Use this number even if the author’s name is included in the sentence. Example:  ...Smith reports that incidence rates are declining.29
  • Cited works appear in the reference list in the order in which they were cited, NOT alphabetized by first author.
  • Use the number originally assigned to the reference each time you cite the work. 
  • Place reference numbers outside periods and commas and inside colons and semi-colons.




1.  Patrias K, author; Wendling D, editor. Citing Medicine: The NLM Style Guide for Authors, Editors, and Publishers [Internet]. 2nd edition. Bethesda (MD): National Library of Medicine (US); 2007 [cited 2018 May 10]. Available from:

2.  International Committee of Medical Journal Editors (ICMJE) . Recommendations for the Conduct, Reporting, Editing and Publication of Scholarly Work in Medical Journals [Internet].  ICMJE. Updated December 2017 [cited 2018 May 10]. Available from:



Slide Presentation

The ICMJE Recommendations does not offer advice on how to cite within a PowerPoint, however one can assume that like an article this format needs citations. 

General Rules:

  • Cite pertinent references
  • List the references on the last slide
  • Remember to use the National Library of Medicine (NLM) citation format

Scientific Poster

Examples are forthcoming.

Recommended Resources

Web Links