This guide will help you properly cite sources in NLM format, ensuring your academic work meets the necessary standards for medical and biomedical papers. NLM style underlies the reference format used in PubMed, MEDLINE, and many medical journals. If you're writing for biomedical publications or citing clinical research, mastering NLM style is essential.
Jan 3, 2026
By
Joe Pacal, MSc
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TL;DR
NLM style offers citation-sequence, citation-name, and name-year systems. This guide covers reference formats for journals (using NLM Catalog abbreviations), books, databases, and clinical resources. Access dates required for online sources. Very similar to Vancouver—both stem from ICMJE. Perfect for biomedical research and life sciences.
Official Source
NLM style is the citation format developed by the National Library of Medicine, used extensively in biomedical research, medical journals, and life sciences publications. The authoritative guide is Citing Medicine: The NLM Style Guide for Authors, Editors, and Publishers, a comprehensive free resource maintained by the National Institutes of Health.
Quick Overview: NLM Citation Format
NLM offers three in-text citation systems:
Citation-Sequence: Sources numbered in the order they appear; reference list follows the same order.
Citation-Name: Sources numbered alphabetically; numbers used in text regardless of appearance order.
Name-Year: Author surnames and years in parentheses; references listed alphabetically.
Most biomedical journals use citation-sequence, but always verify with your target journal's requirements.
Key NLM characteristics:
Author initials without periods or spaces
Abbreviated journal titles per NLM/MEDLINE standards
Access dates required for online sources
Punctuation carefully specified
In-Text Citations in NLM
Citation-Sequence System
Number sources as they first appear:
Chocolate has many potential health benefits such as improved blood flow¹ and cognitive function².
For multiple sources: ...documented extensively¹,² or ...in several studies¹⁻³,⁵
Citation-Name System
Numbers correspond to alphabetical reference list:
Chocolate has many potential health benefits such as improved blood flow¹¹ and cognitive function¹⁰.
Name-Year System
Recent studies (Morrison 2024) have documented...multiple researchers (Smith 2023; Chen and Wong 2024) confirm...
Reference List Format
Journal Articles
Standard print article:
Article with more than 6 authors:
Note: NLM now lists all authors, but using "et al." after the sixth author remains acceptable.
Article with DOI:
Online journal article:
Books
Single author:
Edited book:
Book with edition:
Book Chapters
Websites and Homepages
Website with organization as author:
Databases
Dissertations
Conference Papers
Clinical Practice Guidelines and Databases
UpToDate:
DailyMed:
NLM Journal Abbreviations
NLM uses standardized journal abbreviations from the NLM Catalog. Common examples:
Full Title | NLM Abbreviation |
|---|---|
New England Journal of Medicine | N Engl J Med |
Journal of the American Medical Association | JAMA |
British Medical Journal | BMJ |
Annals of Internal Medicine | Ann Intern Med |
The Lancet | Lancet |
Nature Medicine | Nat Med |
Cell | Cell |
Neurology | Neurology |
Search the NLM Catalog for correct abbreviations.
Common NLM Mistakes to Avoid
Missing access dates: For all internet sources, include "[cited YYYY Mon DD]" to document when you accessed the content.
Incorrect author formatting: Use initials without periods or spaces: "Smith JK" not "Smith, J.K." or "Smith J. K."
Wrong journal abbreviations: Always verify abbreviations against the NLM Catalog—incorrect forms are a common error.
Omitting "Available from": Internet sources require "Available from:" followed by the URL.
Forgetting edition or update information: For resources that change, include edition, update date, or revision information.
NLM Citation Tools
PubMed provides formatted citations—click "Cite" on any article record for NLM-formatted references.
Reference managers like Zotero include NLM/Vancouver style templates. Since NLM and Vancouver are closely related, Vancouver templates typically work for NLM requirements.
For organizing biomedical literature and research, Wonders AI helps researchers discover sources and maintain properly formatted citations.
References
Patrias K, Wendling D, editors. Citing Medicine: The NLM Style Guide for Authors, Editors, and Publishers [Internet]. 2nd ed. Bethesda (MD): National Library of Medicine (US); 2007- [updated 2015 Oct 2; cited 2025 Jan 2]. Available from: http://www.nlm.nih.gov/citingmedicine
National Library of Medicine. Samples of Formatted References for Authors of Journal Articles [Internet]. Bethesda (MD): NLM; [cited 2025 Jan 2]. Available from: https://www.nlm.nih.gov/bsd/uniform_requirements.html
Medical University of South Carolina Libraries. National Library of Medicine (NLM) Citation Style [Internet]. Charleston (SC): MUSC; [cited 2025 Jan 2]. Available from: https://musc.libguides.com/NLM
Middlebury College Library. NLM Citation & Style Guide [Internet]. Middlebury (VT): Middlebury College; [cited 2025 Jan 2]. Available from: https://middlebury.libguides.com/citation/nlm
