Your medical school’s handbook says “references in Vancouver style”, and your reference manager offers three different Vancouver options. Which rules are fixed, and which depend on the journal or university? Vancouver referencing is a numbered system: each source receives a number in the order it is first cited, and the reference list follows that numerical order. Its rules come from the ICMJE Recommendations and the US National Library of Medicine (NLM), which is why it dominates biomedical journals and medical theses.
This article is part of our guide How to Write a Master’s Thesis by the Mastermind PhD team and relates to our Thesis & Research Formatting service. Sources last checked: November 2026.
This guide sets out the core rules, gives examples you can adapt, and lists the points to check against your own university’s guide.
What is Vancouver referencing? Vancouver referencing is the citation format recommended by the International Committee of Medical Journal Editors (ICMJE), with detailed rules in the NLM’s Citing Medicine (2nd edition). Sources are identified in the text by Arabic numerals, numbered consecutively in order of first mention, and listed in that order at the end, with journal titles abbreviated as in MEDLINE.
Where does Vancouver referencing come from?
The name goes back to a 1978 meeting of medical journal editors in Vancouver, which produced uniform requirements for manuscripts. Today the ICMJE Recommendations state the core rules, and the NLM provides the detailed formats: Citing Medicine for every type of source and a page of sample references for the most common ones. University guides and journals then add local preferences, such as square brackets instead of parentheses.
What are the 7 core rules of Vancouver referencing?
- Number in order of first citation. The ICMJE says references “should be numbered consecutively in the order in which they are first mentioned in the text.”
- Reuse the number. A source cited again keeps its original number; it is never given a new one.
- Arabic numerals in the text. ICMJE asks for numerals in parentheses, such as (3); many universities and journals use square brackets [3] or superscript³. Follow your handbook and be consistent.
- Tables and figures follow the text. References cited only in a table or figure legend are numbered according to where that table or figure is first mentioned in the text.
- Abbreviate journal titles as in MEDLINE. The New England Journal of Medicine becomes N Engl J Med. Check abbreviations in the NLM Catalog.
- Authors: surname plus initials, no full stops. The NLM sample references list the first six authors followed by “et al.” when there are more than six; the NLM itself now lists all authors in its database. Your university may set a different limit.
- Minimal punctuation. No italics or quotation marks for titles in the classic NLM format; the year, volume, issue and pages are run together: 2002;347(4):284-7.
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How do you cite in the text with Vancouver referencing?
The number replaces the author and year:
- Single source: Smoking increases the risk of postoperative complications (4).
- Several sources: Earlier trials reported similar effects (2,5,7).
- A range: Several cohorts confirmed the finding (3-6).
- Naming the author: Halpern et al. (1) argued that transplantation is feasible in selected patients.
Place the number consistently, usually before the full stop and comma when you use parentheses or brackets. Superscript numbers are often placed after punctuation; check the convention in your guide.
What do Vancouver references look like? Examples
The examples below follow the NLM sample references page. Use them as templates.
| Source type | Example |
|---|---|
| Journal article (up to 6 authors) | Halpern SD, Ubel PA, Caplan AL. Solid-organ transplantation in HIV-infected patients. N Engl J Med. 2002 Jul 25;347(4):284-7. |
| Journal article (more than 6 authors) | Rose ME, Huerbin MB, Melick J, Marion DW, Palmer AM, Schiding JK, et al. Regulation of interstitial excitatory amino acid concentrations after cortical contusion injury. Brain Res. 2002;935(1-2):40-6. |
| Book | Murray PR, Rosenthal KS, Kobayashi GS, Pfaller MA. Medical microbiology. 4th ed. St. Louis: Mosby; 2002. |
| Website | eatright.org [Internet]. Chicago: Academy of Nutrition and Dietetics; c2016 [cited 2016 Dec 27]. |
For an online article with a DOI, many guides add it at the end (for example “doi: 10.xxxx/xxxxx”). For a thesis, a book chapter, a guideline or a dataset, look up the exact format in Citing Medicine, which has a chapter for each type of source.
How should you manage Vancouver referencing in a long thesis?
Numbering by first mention is the main practical difficulty. If you move a paragraph from chapter 4 to chapter 2, every number after it changes. Doing this by hand across 150 references is where most errors appear.
- Use a reference manager. Zotero, EndNote and Mendeley include Vancouver styles and renumber automatically when text moves. Pick the variant that matches your university guide, then check one example of each source type by hand.
- Decide on chapter or whole-thesis numbering. Some medical schools number references continuously across the thesis with one list at the end; others want a list per chapter. The handbook decides.
- Freeze late. Do not convert citation fields to plain text until the final version, or renumbering stops working.
- Keep tables and figures in sequence. When a table is first mentioned in chapter 3 but cites a source already used in chapter 1, the source keeps its chapter 1 number. New sources cited only in that table take the next numbers in sequence at the point where the table is first mentioned.
- Run a final audit. Before submission, read the list from 1 to the end and confirm that each number appears in the text, in ascending order of first appearance, and that no source appears twice under different numbers. This ten-minute check catches the duplicates that reference managers create when the same article was imported twice.
- Check retractions. ICMJE makes authors responsible for not citing retracted articles except when discussing the retraction; PubMed flags them.
What are the most common Vancouver referencing errors?
| Error | Correct practice |
|---|---|
| List ordered alphabetically | Order by first citation in the text |
| A repeated source given a new number | Keep the original number |
| Full journal names mixed with abbreviations | Use MEDLINE abbreviations throughout |
| “et al.” after three authors when the guide says six | Follow the limit in your guide |
| Mixed brackets, parentheses and superscript | One format throughout |
| Personal communications in the list | Cite them in the text only, with permission, as ICMJE advises |
A final formatting check catches most of these. The Mastermind PhD team’s thesis formatting starts from EGP 10,500 on the live service page, and every file comes with a Turnitin report.
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Frequently asked questions
Is Vancouver referencing the same as numeric referencing?
Vancouver is one numeric style. IEEE is another, with different punctuation and author formatting, so the two are not interchangeable even though both use numbers.
Do I need the issue number in Vancouver referencing?
The NLM samples include it in parentheses after the volume, such as 347(4). Some university guides allow omitting it when pagination is continuous through the volume; follow your guide.
Where do I find the correct journal abbreviation?
In the NLM Catalog (the journals database at the NLM), which gives the MEDLINE abbreviation for indexed journals. Do not invent abbreviations for journals that are not listed.
Can I cite secondary sources?
Cite the source you actually read. If you quote a study you only saw cited in a review, cite the review, and ideally obtain and read the original.
Does the reference list count toward my word limit?
In most programs it does not, but the handbook decides. Check whether in-text numbers and table references are counted.
Sources
- International Committee of Medical Journal Editors. Preparing a Manuscript for Submission to a Medical Journal: References. https://www.icmje.org/recommendations/browse/manuscript-preparation/preparing-for-submission.html (accessed November 2026)
- National Library of Medicine. Samples of Formatted References for Authors of Journal Articles. https://www.nlm.nih.gov/bsd/uniform_requirements.html (accessed November 2026)
- Patrias K, author; Wendling D, editor. Citing Medicine: The NLM Style Guide for Authors, Editors, and Publishers. 2nd ed. Bethesda (MD): National Library of Medicine (US); 2007-. https://www.ncbi.nlm.nih.gov/books/NBK7256/
- National Library of Medicine. NLM Catalog. https://www.ncbi.nlm.nih.gov/nlmcatalog/journals (accessed November 2026)
Sources last checked: November 2026. This article is general educational guidance and does not replace your university regulations or your supervisor’s instructions. How we prepare our content.