Reference Style and Recommendations - References

AMA Manual of Style - Stacy L. Christiansen, Cheryl Iverson 2020

Reference Style and Recommendations

References serve 3 primary purposes—documentation, acknowledgment, and directing or linking the reader to additional resources. Authors may cite a reference to support their own arguments or lay the foundation for their theses (documentation), to credit the work of other authors (acknowledgment), or to direct the reader to more detail or additional resources (directing or linking).

References are a critical element of a scientific manuscript, and, as such, the reference list demands scrutiny by authors, editors, peer reviewers, manuscript editors, and proofreaders. Authors bear primary responsibility for all reference citations. Editors and peer reviewers should examine manuscript references for completeness, accuracy, and relevance. Manuscript editors and proofreaders are responsible for assessing the completeness of references, ensuring that references are presented in proper style and format, and checking to make sure that any reference links are accurate and functional.

Much has been written about problems with bibliographic inaccuracies1 (eg, an author’s name is misspelled, the journal’s name is incorrect, the year of publication or the volume, issue, or page numbers are incorrect). Such errors make it difficult to retrieve the documents cited. An even more serious problem is inappropriate citation, for example,

■a speculative commentary cited in a way that implies proved causality;

■an article’s results generalized beyond what the data support;

■a retracted article cited without acknowledging the retraction in the citation;

■an article from a predatory journal cited.

Not only is accuracy critical for the integrity of the individual document, but because authors may sometimes rely on secondary rather than primary sources, an inaccurate citation in a document’s reference list may be replicated in subsequent articles whose authors do not consult the primary source. Authors should always consult the primary source and should never cite a reference that they themselves have not read2 (see 3.11.10, Abstracts Taken From Another Source).

3.1 Reference Style and Recommendations.

For greater uniformity in technical requirements for manuscripts submitted to their journals, the International Committee of Medical Journal Editors (ICMJE) developed in 1978 the Uniform Requirements for Manuscripts Submitted to Biomedical Journals (URMs).3 (The ICMJE was originally referred to as the Vancouver group because the first meeting was in Vancouver, Canada; thereafter, the term Vancouver style was coined for the author-number system of reference citations.) In 2013, the Uniform Requirements was renamed to the ICMJE Recommendations for the Conduct, Reporting, Editing, and Publication of Scholarly Work in Medical Journals (or ICMJE Recommendations).3

Suggested formats for bibliographic style have been developed for uniformity by the US National Library of Medicine (NLM) and are available as sample references on the NLM website in the document “Samples of Formatted References for Authors of Journal Articles,”4 as mentioned in the ICMJE Recommendations. Details for this document, including “fuller citations and explanations,” are provided in Citing Medicine: The NLM Style Guide for Authors, Editors, and Publishers,5 which is also published by the NLM and is frequently updated. The recommended style is based on the National Information Standards Organization (NISO) standard for Bibliographic References, ANSI/NISO Z39.29-2005 (R2010),6 and the NLM has adapted these standards for scientific material in its databases.

These documents3,4,5,6 (see Box 3.1-1) are intended to aid authors in the preparation of their manuscripts for publication and are not meant to dictate reference style to journal editors, although many journal editors have modified their reference styles to more or less follow these guidelines.3 Many journals will accept manuscripts for consideration using these reference styles but will reformat them to their own style before publication. Authors and publishers may use reference management software to help ensure reference accuracy.

The reference style followed by the JAMA Network journals is also based on recommendations described in Citing Medicine.5 The reference style of the JAMA Network journals and that of the ICMJE Recommendations represent modifications of the NLM style but follow the general principles outlined in Citing Medicine. Note: Citing Medicine follows the NISO Bibliographic References standard, but NLM practice does not always follow the NISO standard in MEDLINE/PubMed citations.7

Whatever reference style is followed, consistency throughout the document and throughout the publication (journal, book, website) is critical.

Box 3.1-1. Recommendation Documents

Year released

Last updated





Recommendations for the Conduct, Reporting, Editing, and Publication of Scholarly Work in Medical Journals (updates the URMs)




Citing Medicine: The NLM Style Guide for Authors, Editors, and Publishers




ANSI/NISO Z39.29-2005 (R2010) Bibliographic References




Samples of Formatted References for Authors of Journal Articles



Uniform Requirements for Manuscripts Submitted to Biomedical Journals (URMs)

ICMJE (the Vancouver group)

3.1.1 Bibliographic Grouping.

Each reference is divided with periods into bibliographic groups (see 3.4, Minimum Acceptable Data for References, for an illustration of these for the principal types of references). The period serves as a field delimiter, making each bibliographic group distinct and establishing a sequence of bibliographic elements in a reference. Bibliographic elements are the items within a bibliographic group. Bibliographic elements may be separated by the following punctuation marks:

A comma: if the items are subelements of a bibliographic element or a set of closely related elements (eg, the authors’ names in the reference list)

A semicolon: if the elements in the bibliographic group are different (eg, between the publisher’s name and the copyright year) or if there are multiple occurrences of logically related elements within a group; also, before volume identification data

A colon: between the title and the subtitle and after a connective and/or descriptive phrase (eg, “In,” “Presented at,” “Video supplement to,” “Interactive feature for,” “Videocast available at,” “Retracted in”); also, before page numbers and article IDs or e-locators