The Vancouver system, also known as Vancouver reference style or the author–number system, is a citation style that uses numbers within the text that refer to numbered entries in the reference list. It is popular in the physical sciences and is one of two referencing systems normally used in medicine, the other being the author–date, or "Harvard", system. Vancouver style is used by MEDLINE and PubMed.
Hundreds of scientific journals use author-number systems. They all follow the same essential logic (that is, numbered citations pointing to numbered list entries), although the trivial details of the output mask, such as punctuation, casing of titles, and italic, vary widely among them. They have existed for over a century; the names "Vancouver system" or "Vancouver style" have existed since 1978. The latest version of the latter is Citing Medicine, per the References > Style and Format section of the ICMJE Recommendations.
In the broad sense, the Vancouver system refers to any author-number system regardless of the formatting details. A narrower definition of the Vancouver system refers to a specific author-number format specified by the ICMJE Recommendations (Uniform Requirements for Manuscripts, URM). For example, the AMA reference style is Vancouver style in the broad sense because it is an author-number system that conforms to the URM, but not in the narrow sense because its formatting differs in some minor details from the NLM/PubMed style (such as what is italicized and whether the citation numbers are bracketed).
Author–number systems have existed for over a century and throughout that time have been one of the main types of citation style in scientific journals (the other being author–date). In 1978, a committee of editors from various medical journals, the International Committee of Medical Journal Editors (ICMJE), met in Vancouver, BC, Canada to agree to a unified set of requirements for the articles of such journals. This meeting led to the establishment of the Uniform Requirements for Manuscripts Submitted to Biomedical Journals (URMs). Part of the URMs is the reference style, for which the ICMJE selected the long-established author–number principle.
The URMs were developed 15 years before the World Wide Web debuted. During those years, they were published as articles or supplements in various ICMJE member journals. These included the 1991 BMJ publication, the 1995 CMAJ publication and the 1997 Annals of Internal Medicine publication. In the late 1990s and early 2000s, journals were asked to cite the 1997 JAMA version when reprinting the Uniform requirements.
In the early 2000s, with the Web having become a major force in academic life, the idea gradually took hold that the logical home for the latest edition of the URMs would be the ICMJE website itself (as opposed to whichever journal article or supplement had most recently published an update). For example, as of 2004, the editors of Haematologica decided simply to invite their authors to visit www.icmje.org for the 2003 revision of the Uniform requirements.
Since the early to mid-2000s, the United States National Library of Medicine (which runs MEDLINE and PubMed) has hosted the ICMJE's "Sample References" pages. Around 2007, the NLM created Citing Medicine, its style guide for citation style, as a new home for the style's details. The ICMJE Recommendations now point to Citing Medicine as the home for the formatting details of Vancouver style. For example, in the December 2013 edition of the ICMJE Recommendations, the relevant paragraph is IV.A.3.g.ii. (References > Style and Format).
References are numbered consecutively in order of appearance in the text – they are identified by Arabic numerals in parentheses(1), square brackets, superscript1, or a combination. 1. Xu, Y.Z.; Geng, D.C.; Mao, H.Q.; Zhu, X.S.; Yang, H.L A comparison of the proximal femoral nail antirotation device and dynamic hip screw in the treatment of unstable pertrochanteric fracture. J Int Med Res. 2010, 38, 1266-1275. 2. Handoll, H.H.; Parker, M.J. Conservative versus operative treatment for hip fractures in adult. Cochrane Database Syst Rev. 2008, 16, CD000337. 3. Pu, J.S.; Liu, L.; Wang, G.L.; Fang, Y.; Yang,TF. Results of the proximal femoral nail anti-rotation (PFNA) in elderly chinese patients. Int Orthop. 2009, 33, 1441-1444. 4. Jones, H.W.; Johnston, P.; Parker, M. Are short femoral nails superior to the sltiding hip screw? A meta-analysis of 24 studies involving 3, 279 fractures. Int Orthop. 2006, 30, 69-78. 5. Zeng, C.; Wang, Y.R.; Wei, J.; Gao, S.G.; Zhang, F.J.; Sun, Z.Q.; Lei, G.H. Treatment of trochanteric fractures with proximal femoral nail antirotation or dynamic hip screw systems: a meta-analysis. J Int Med Res. 2012, 40, 839-851. 6. Barquet, A.; Francescoli, L.; Rienzi, D.; Lopez, L. Intertrochanteric-subtrochanteric fractures: treatment with the long Gamma nail. J Orthop Trauma. 2000, 14,324-328. 7. Haidukewych, G.; Israel, A.; Berry, D. Reverse obliquity fractures of the intertrochanteric region of the femur. J Bone Joint Surg Am. 2001, 38, 643-650. 8. Carulli C, Piacentini F, Paoli T, Civinini R, Innocenti M. A comparison of two fixation methods for femoral trochanteric fractures: a new generation intramedullary system vs sliding hip screw. Clin Cases Miner Bone Metab. 2017, 14, 40-47. Doi: 10.11138/ccmbm/2017.14.1.040. 9. Curtis, M.J.; Jinnah R.H.; Wilson V.; Cunningham, B.W. Proximal femoral fractures: a biomechanical study to compare intramedullary and extramedullary fixation. Injury. 1994, 25, 99-104. 10. PFNA (2004) Leading the way to optimal stability: synthes. Original instruments and implants of the association for the study of Internal Fixation. AO/ASIF. Stratec Medical, Oberdorf, pp 1-44. 11. Mereddy, P.; Kamath, S.; Ramakrishnan, M.; Malik, H.; Donnachie N. The AO/ASIF proximal femoral nail antirotation (PFNA): A new design for the treatment of unstable proximal femoral fractures. Injury, Int. J. Care Injured. 2009, 40, 428-432. 12. Harris, W.H. Traumatic arthritis of the hip after dislocation and acetabular fractures: treatment by mold arthroplasty. An end-result study using a new method of result evaluation. J Bone Joint Surg Am. 1969, 51, 737-55. 13. Zhang, H.; Zhu, X.; Pei, G.; Zeng, X.; Zhang, N.; Xu, P.; et al. A retrospective analysis of the InerTan nail and proximal femoral nail anti-rotationin in the treatment of intertrochanteric fractures in elderly patients with osteoporosis: a minimum follow-up of 3 years. J Orthop Surg Res. 2017, 12, 147 DOI 10.1186/s13018-017-0648-2 14. Sommers, M.B.; Roth, C.; Hall, H.; et al. A laboratory model to evaluate cut out resistance of implants for pertrochanteric fracture fixation. J Orthop Trauma. 2004, 18, 361-368. DOI: 10. 1097/00005131-200407000-00006 15. Hwang, J.H.; Oh, J.K.; Oh, C.W.; Lee S.J., Myung-Rae, C.; Kim H.; Kim, M.K. A biomechanical evaluation of proximal femoral nail antirotation with respect to helical blade position in femoral head: A cadaveric study. Indian J O. 2012, 46, 627-632. 16. Banan, H.; Al-Sabti, A.; Jimulia, T.; Hart, A.J.; The treatment of unstable, extracapsular hip fractures with the AO/ASIF proximal femoral nail (PFN)—our first 60 cases. Injury, Int. J. Care Injured. 2002, 33, 401–405. 17. Simmermacher, R.K.; Bosch, A.M.; Van der Werken C. The AO/ASIF-proximal femoral nail (PFN): a new device for the treatment of unstable proximal femoral fractures. Injury. 1999, 30, 327–332. 18. Takigami, I.; Matsumoto, K.; Ohara, A.; et al. Treatment of trochanteric fractures with the PFNA (proximal femoral nail antirotation) Nail system–report of early results. Bull NYU Hosp Jt Dis. 2008, 66, 276–279. 19. Al-yassari, G.; Langstaff, R.J.; Jones, J.W.M.; Al-Lami, M. The AO/ASIF proximal femoral nail (PFN) for the treatment of unstable trochanteric femoral fracture. Injury. 2002, 33, 395–399. 20. Herrera, A.; Domingo, L.J.; Calvo, A.; Martinez, A. A comparative study of trochanteric fractures treated with Gamma nail or the proximal femoral nail. Int Orthop. 2002, 26, 365-369. 21. Albareda, J.; Laderiga, A.; Palanca, D.; et al. Complications and technical problems with gamma nail. Int Orthop. 1996, 20, 4750. 22. Aguado-Maestro, .I; Escudero-Marcos, R.; Garcia-Garcia, J.M.; Alonso-Garcia, N.; Perez-Bermejo, D.D.; Aguado-Hernandez, H.J.; et al. Results and complications of pertrochanteric hip fractures using an intramedullary nail with a helical blade (proximal femoral nail antirotation) in 200 patients]. Revista espanola de cirugia ortopedica y traumatologia. 2013, 57, 201-207. 23. Şahin, E.K.; İmerci, A.; Kınık, H.; Karapınar, L.; Canbek, U.; Savran, A. Comparison of proximal femoral nail antirotation (PFNA) with AO dynamic condylar screws (DCS) for the treatment for unstable peritrochanteric femoral fracture. Eur J Orthop Surg Traumatol. 2014, 24, 347–352. 24. Karapınar, L.; Kumbaracı, M.; Kaya, A.; Imerci, A.; Incesu M. Proximal femoral nail anti-rotation (PFNA) to treat peritrochanterics in elderly patients. Eur J Ortho Surg traumatol. 2011,5,1-7. 25. Simmermacher, R.K.; Ljungqvist, J.; Bail, H.; et al. The new proximal femoral nail antirotation (PFNA) in daily practice: Results of a multicentre clinical study. Injury. 2008, 39, 932–939. 26. Yu, W.; Zhang, X.; Zhu, X.; Hu, J.; Liu, Y. A retrospective analysis of the InterTan nail and proximal femoral nail anti-rotation-Asia in the treatment of unstable intertrochanteric femur fractures in the elderly. J Orthop Surg Res. 2016, 11 27. Macheras, G.A.; Galanakos, S.P.; Koutsostathis, S.; Kateros, K.; Karras, A.; Papadakis, S.A. Unstable pertrochanteric Fractures. A comparison of preliminary results using three different methods of fixation. EEXOT. 2013, 64, 25-33
Several descriptions of the Vancouver system say that the number can be placed outside the text punctuation to avoid disruption to the flow of the text, or be placed inside the text punctuation, and that there are different cultures in different traditions. The first method is recommended by some universities and colleges, while the latter method is required by scientific publications such as the MLA and IEEE except for in the end of a block quotation. (IEEE are using Vancouver style labels within brackets, for example  to cite the first reference in the list, but otherwise refer to Chicago Style Manual). The original Vancouver system documents (the ICMJE recommendations and Uniform Requirements for Manuscripts Submitted to Biomedical Journals) do not discuss placement of the citation mark.
Format of citations
Different formats exist for different types of sources, e.g. books, journal articles etc. Author names are abbreviated to at most two initials. Although Citing Medicine does not explicitly mandate merging initials (e.g. "R. K." would be merged into "RK"), the examples used throughout the book do.
Standard journal articles
- Leurs R, Church MK, Taglialatela M. H1-antihistamines: inverse agonism, anti-inflammatory actions and cardiac effects. Clin Exp Allergy. 2002 Apr;32(4):489-498.
- Tashiro J, Yamaguchi S, Ishii T, Suzuki A, Kondo H, Morita Y, Hara K, Koyama I. Inferior oncological prognosis of surgery without oral chemotherapy for stage III colon cancer in clinical settings. World J Surg Oncol. 2014 May 10;12(1):145. [Epub ahead of print]
As an option, if a journal carries continuous pagination throughout a volume (as many medical journals do), the month and issue number may be omitted.
- Thomas MC. Diuretics, ACE inhibitors and NSAIDs – the triple whammy. Med J Aust. 2000;172:184-185.
The NLM lists all authors for all articles, because it is appropriate for capturing all authors and all of their publications in the MEDLINE database to be found by searches. However, in the reference lists of articles, most journals truncate the list after 3 or 6 names, followed by "et al." (which most medical journals do not italicize):
- Guilbert TW, Morgan WJ, Zeiger RS, Mauger DT, Boehmer SJ, Szefler SJ, et al. Long-term inhaled corticosteroids in preschool children at high risk for asthma. N Engl J Med. 2006 May 11;354(19):1985-1997.
Optionally, a unique identifier (such as the article's DOI or PMID) may be added to the citation:
- von Itzstein M, Wu WY, Kok GB, Pegg MS, Dyason JC, Jin B, et al. Rational design of potent sialidase-based inhibitors of influenza virus replication. Nature. 1993 Jun 3;363(6428):418-423. PMID 8502295.
NLM elides ending page numbers and uses a hyphen as the range indicating character (184-5). Some journals do likewise, whereas others expand the ending page numbers in full (184-185), use an en dash instead of a hyphen (184–5), or both (184–185).
Virtually all medical journal articles are published online. Many are published online only, and many others are published online ahead of print. For the date of online publication, at the end of the citation NLM puts "[Epub Year Mon Day]" (for online-only publication) or "[Epub ahead of print]" for online ahead of print (with the month and day following the year in its normal position). In contrast, AMA style puts "[published online Month Day, Year]" at the end of the article title. It no longer uses the term "Epub" and no longer includes the words "ahead of print". It omits the year from its normal location after the journal title abbreviation if there is no print data to give (online-only publication).
The titles of journals are abbreviated. There are no periods in the abbreviation. A period comes after the abbreviation, delimiting it from the next field. The abbreviations are standardized. The standardization was formerly incomplete and internal to organizations such as NLM. It is now formalized at the supraorganizational level by documents including Citing Medicine at Appendix A: Abbreviations for Commonly Used English Words in Journal Titles, ANSI Z39.5, ISO 4: Information and documentation -- Rules for the abbreviation of title words and titles of publications, and the ISSN.org List of Title Word Abbreviations (LTWA).
Articles not in English
As per journal articles in English:
- Forneau E, Bovet D. Recherches sur l'action sympathicolytique d'un nouveau dérivé du dioxane. Arch Int Pharmacodyn. 1933;46:178-191. French.
The NLM adds an English translation of the title enclosed in square brackets right after the title. The language is specified in full after the location (pagination), followed by a period.
- Rang HP, Dale MM, Ritter JM, Moore PK. Pharmacology. 5th ed. Edinburgh: Churchill Livingstone; 2003.
Editor(s) or compiler(s) as authors
- Beers MH, Porter RS, Jones TV, Kaplan JL, Berkwits M, editors. The Merck manual of diagnosis and therapy. 18th ed. Whitehouse Station (NJ): Merck Research Laboratories; 2006.
Authored chapter in edited publication
- Glennon RA, Dukat M. Serotonin receptors and drugs affecting serotonergic neurotransmission. In: Williams DA, Lemke TL, editors. Foye's principles of medicinal chemistry. 5th ed. Philadelphia: Lippincott Williams & Wilkins; 2002.
- World Health Organization (WHO). Mortality country fact sheet 2006 [internet]. Geneva: WHO; 2006. Available from: www.who.int/whosis/mort_emro_pak_pakistan.pdf
- ^Reference styles [Retrieved 2016-10-04].
- ^International Committee of Medical Journal Editors (ICMJE) Uniform Requirements for Manuscripts Submitted to Biomedical Journals: Sample References, United States National Library of Medicine, retrieved 2013-03-01
- ^Patrias K, Wendling D, ed., Citing Medicine: The NLM Style Guide for Authors, Editors, and Publishers, Bethesda, Maryland, USA: United States National Library of Medicine.
- ^ abcICMJE, Recommendations for the Conduct, Reporting, Editing, and Publication of Scholarly Work in Medical Journals(PDF).
- ^International Committee of Medical Journal Editors. Uniform requirements for manuscripts submitted to biomedical journals.. BMJ (Clinical research ed.). 1991;302(6772):338–341. doi:10.1136/bmj.302.6772.338. PMID 2001512.
- ^International Committee of Medical Journal Editors. Uniform requirements for manuscripts submitted to biomedical journals.. Canadian Medical Association Journal. 1995;152(9):1459–1473. PMID 7728695.
- ^International Committee of Medical Journal Editors. Uniform requirements for manuscripts submitted to biomedical journals. [Free full text]. Annals of Internal Medicine. 1997;126(1):36–47. doi:10.7326/0003-4819-126-1-199701010-00006. PMID 8992922.
- ^International Committee of Medical Journal Editors. Uniform requirements for manuscripts submitted to biomedical journals.. JAMA: The Journal of the American Medical Association. 1997;277(11):927–934. doi:10.1001/jama.277.11.927. PMID 9062335.
- ^International Committee Of Medical Journal Editors (ICMJE). Uniform Requirements for Manuscripts Submitted to Biomedical Journals: writing and editing for biomedical publication [Free full text]. Haematologica. 2004;89(3):264. PMID 15020262.
- ^International Committee of Medical Journal Editors. Uniform Requirements for Manuscripts Submitted to Biomedical Journals: Sample References [Retrieved 2006-12-24].
- ^University of Leicester. Vancouver (Numbered) System.
- ^Department of Forensic Medicine, Govt. Medical College, Patiala. Reference systems deciphered for you.
- ^Vancouver Community College. Vancouver Citation Style. "The citation in brackets is placed after any commas and periods, and before any colons and semi-colons"
- ^Cornell University Library. MLA Citation Style.
- ^ abIEEE Citation Reference. "References ... appear on the line, in square brackets, inside the punctuation."
- ^Citing Medicine: The NLM Style Guide for Authors, Editors, and Publishers [Internet]. 2nd ed. Bethesda, MD: National Library of Medicine (US); 2007 [Retrieved 2012-02-22]. "Convert given (first) names and middle names to initials, for a maximum of two initials following each surname"
Many medical institutions maintain their own style guides, with information on how to cite sources:
Before using this guide check with your faculty, school or department for their specific referencing guidelines.
Follow these examples closely for all layout, punctuation, spacing and capitalization.
Enter author's surname, followed by no more than 2 initials.
Only the first word of the Thesis / Dissertation title and words that normally begin with a capital letter are capitalized.
The place of publication is the city in which the conferring institution is located. For US and Canadian cities follow with the two letter state code in Appendix E, for all other cities us the two letter country code in Appendix D
In cases where the place of publication is not stated, source the location via alternative methods e.g. location of University and place this in square brackets.
Abbreviate months to their first 3 letters
Insert Dissertation for a PhD or master's thesis for a master's degree in square brackets [ ] following the title.
If you are estimating the number of pages include the p. after the page number, if you know how many pages that are in the thesis/dissertation, include the p. before the page number
For further details on citing Theses / Dissertations refer to Chapter 5 - Dissertations and Theses in Citing Medicine.
Author AA. Title of thesis [dissertation]. Place of publication: Publisher; Year. Number of pages
O’Brien KA. The philosophical and empirical intersections of Chinese medicine and western medicine [dissertation]. Melbourne, AU; Monash University; 2006. 439 p.
Weisbaum LD. Human sexuality of children and adolescents: a comprehensive training guide for social work professionals [master's thesis]. Long Beach (CA): California State University; 2005. 200 p.
For electronic Theses / Dissertations include in the citation "on the internet" inside the square brackets, next to the title.
Also include the date viewed/cited
Author AA. Title of thesis [dissertation on the Internet]. Place of publication: Publisher; Year. [cited YYYY abb. month DD]. Available from: URL
Bianchi M. Multiscale fabrication of functional materials for regenerative medicine [dissertation on the internet]. Bologna, IT: University of Bologna; 2011. [cited 2012 Dec 07]. Available from: http://ezproxy.lib.monash.edu.au/login?url=http://dx.doi.org/10.1007/978-3-642-22881-0
For electronic Theses / Dissertations include in the citation "on microfiche" inside the square brackets, next to the title.
Author AA. Title of thesis [dissertation on microfiche]. Place of publication: Publisher; Year. Number of pages. microform extent.
Craft LL. Exercise and clinical depression: examining psychological mechanisms [dissertation on microfiche]. East Lansing, MI: Michigan State University; 2002. 116 p. 2 microfiche: black & white, negative, 4 x 6 in.