Numerical, 4-digit year.


Usage: In addition to being used for the year of publication, the <year> is also used to record “historical” events in the publishing cycle, for example, the year the document was accepted or last updated.

The <year> element is used in two contexts: as a part of the metadata concerning the article itself, and as part of a description of a cited work inside a bibliographic reference (<element-citation> or <mixed-citation>).

Best Practice: When possible, the year should be expressed as a 4-digit number, for example, “1776”, “1924”, or “1.02”.

Related Essay: For a discussion on the use of <year>, see Dates in Citations.


calendar Calendar
content-type Type of Content
iso-8601-date ISO-8601 Formatted Date
specific-use Specific Use
xml:lang Language

Related Elements

Within citations (<element-citation> and <mixed-citation>), this element is used to name the date of publication. The elements <year>, <date>, <day>, <month>, and <season> may all be used to describe the date a cited resource was published. Other dates inside a citation, such as a copyright date, the date on which the author accessed the resource, or a withdrawal date, should be tagged using <date-in-citation> with the @content-type attribute used to name the type of date (copyright, access-date, time-stamp, etc.).

Content Model

<!ELEMENT  year         (#PCDATA)                                    >


Text, numbers, or special characters

This element may be contained in:

<access-date>, <conf-date>, <date>, <date-in-citation>, <element-citation>, <mixed-citation>, <nlm-citation>, <product>, <pub-date>, <related-article>, <related-object>, <std>, <string-date>

Example 1

In article metadata:

<pub-date pub-type="pub" iso-8601-date="1999-03-27">
<day>27</day> <month>03</month>
<volume>318</volume> <issue>7187</issue>
<fpage>837</fpage> <lpage>841</lpage>
<date date-type="accepted" iso-8601-date="1999-01-29">
<day>29</day> <month>01</month>

Example 2

In an element-style bibliographic reference (punctuation and spacing removed):

<ref id="B8"><label>8</label>
<article-title>Effects and costs of day-care services
for the chronically ill: a randomized experiment</article-title>
<source>Medical Care</source>
<year iso-8601-date="1980">1980</year>
<pub-id pub-id-type="pmid">6772889</pub-id>

Example 3

In a mixed-style bibliographic reference (punctuation and spacing preserved):

<ref id="B8"><label>8</label>
<article-title>Effects and costs of day-care services
for the chronically ill: a randomized experiment</article-title>.
<source>Medical Care</source>
<year iso-8601-date="1980">1980</year>;
<pub-id pub-id-type="pmid">6772889</pub-id>.