A numerical notation system may be less disruptive for the reader than the author–date system, particularly in a document with a large number of references.

This page covers how to use in-text citations using 2 common notation systems: Vancouver and Oxford (documentary-note).

Vancouver

In the Vancouver system, more than 1 note identifier may occur at any single point in the text. A particular reference may be cited many times in the text, but always has the same number. The references may be assembled at the end of each chapter or section, or at the end of the document. The style to use for many reference types is described in Formatting a reference list.

When citing references in the text:

  • number them sequentially as they appear in the document
  • use a superscript number after most punctuation in the text (e.g. after full stops and commas, but before a dash)
  • separate in-text identifiers by commas
  • use a hyphen for a number range (but not for 2 sequential numbers)
  • do not use spaces.

Five methods have been described.2,3,7-9

In the reference list, precede each reference by a nonsuperscripted number.

If this style is used, superscript letters rather than numbers must be used for footnotes, to avoid confusion between references and footnotes. In the text, place notation letters for footnotes before numbers for references.

Oxford (documentary-note)

In the documentary-note system, a single numerical note identifier is used in the text. The note can include multiple citations and commentary. Notes can be placed in footnotes (at the bottom of the page) or as endnotes (at the end of a chapter – useful if the document is to be split into separate chapters for the web – or at the end of the section or the document). In large documents with multiple chapters, footnote numbering usually restarts from 1 for each chapter.

The documentary-note system may be useful in publications with very few citations or those that mostly refer to URLs. A reference list at the back of the publication may not be needed. This system is more commonly used in the humanities than in scientific publications.

Note identifiers in the footnote or endnote can be superscripted (as in the default setting of a word-processing program) or not; do not follow them with a full stop, and insert a tab after the number.

If a note contains both references and comments, list the references before the comments; use a semicolon to separate the entries. Follow the general style in Formatting a reference list. However, because author names do not need to be alphabetically sorted, place author initials before the family name. Punctuate the reference with commas instead of full stops.

First citations

In the text:

Several methods are known to do the job.1

In the footnote, if there is 1 citation:

1   AB Smith (2010), Method 1, Journal of Methods 22:18–35.

In the footnote, if there is more than 1 citation, separate them with a semicolon, and place the full stop only at the end of the note:

1   AB Smith (2010), Method 1, Journal of Methods 22:18–35; CD Jones & AB Smith (2011), The best methods, ABC Publishing, Sydney.

In a footnote that includes citations and notes, present citations first:

1   AB Smith (2010), Method 1, Journal of Methods 22:18–35; CD Jones & AB Smith (2011), The best methods, ABC Publishing, Sydney; Other methods are described by FG Bloggs (2009) in Other methods, XYZ Publishing, Canberra.

Subsequent citations

Several options are available for presenting citations that are referred to more than once. In all cases, use a new note identifier. If there are few footnotes, the full citation can be repeated; however, a shortened form is recommended because it reduces the amount of text in footnotes.

Use the author family name, the title of the publication (in the same format as it appears in the full citation) and, if applicable, a page number. For example, give the title of a book or a journal name, and include other information that may be needed to distinguish mutiple references by the same author(s):

5   Smith & Jones, The best methods, 35.

6   Smith, Journal of Methods.

If there are many notes (and no bibliography), refer to the note where the full citation appears:

40   Smith & Jones, The best methods, 55 (see Chapter 1, note 1).