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<pub-date> Publication Date

Container element for the parts of a single date associated with an article’s publication (for example, date preprint was released, date article was published in print).

Usage/Remarks

Of all the dates concerning an article, the publication date is the most important, for discovery, credit, Crossref and other authority registration, and other uses. Therefore the publication date is tagged using its own semantic <pub-date> element, rather than as a <date> element.
As part of the article metadata (<article-meta>), the element <pub-date> is allowed to repeat; each repetition can take a different @publication-format attribute to distinguish which form of publication (for example, print publication, electronic publication, ePub) and a @date-type attribute to distinguish between preprint, publication, re-release, etc.
While most publication dates will either be a season and a year (for example, Spring 1999) or a year with a possible day and month (for example, January 1, 1999), sometimes the publication date will identify both the season and date. A publication date of “Spring 1999; January 29, 1999” should be tagged: 
<pub-date publication-format="print" date-type="pub"
  iso-8601-date="1999-01-29">
 <season>Spring</season>
 <day>29</day>
 <month>01</month>
 <year>1999</year>
</pub-date>
Attributes
assigning-authority
calendar
date-type
iso-8601-date
publication-format
pub-type

Base Attributes

id
xml:base
xml:lang
Models and Context
May be contained in
<article-meta>, <event>, <event-desc>, <front-stub>
Description
Any combination of:
Content Model
<!ELEMENT  pub-date     %pub-date-model;                             >
Expanded Content Model

(day | era | month | season | year | string-date | x)*

Tagged Samples
Article metadata print publication 
...
<article-meta>
 <article-id pub-id-type="pmid">...</article-id>
 <title-group>...</title-group>
 <contrib-group>...</contrib-group>
 <aff id="StLukes">...</aff>
 <pub-date publication-format="print" date-type="pub" 
   iso-8601-date="1999-03-27">
  <day>27</day>
  <month>03</month>
  <year>1999</year>
 </pub-date>
 <volume>318</volume>
 <issue>7187</issue>
 <fpage>837</fpage>
 <lpage>841</lpage>
 <history>
  <date date-type="accepted" iso-8601-date="2001-01-29">
   <day>29</day>
   <month>01</month>
   <year>1999</year>
  </date>
 </history>
 <permissions>
  <copyright-statement>Copyright &#x00A9; 1999, British
   Medical Journal</copyright-statement>
  <copyright-year>1999</copyright-year>
  <copyright-holder>British Medical Journal</copyright-holder>
 </permissions>
 <abstract>
  <p>To examine the effectiveness of day hospital
   attendance in prolonging independent living for
   elderly people.</p>
 </abstract>
</article-meta>
...
Article metadata multiple dates 
...
<article-meta>
 ...
 <pub-date publication-format="electronic" date-type="pub" iso-8601-date="2015-10-30">
  <day>30</day>
  <month>10</month>
  <year>2015</year>
 </pub-date>

 <pub-date publication-format="print" date-type="pub" iso-8601-date="2016-01-01">
  <day>01</day>
  <month>01</month>
  <year>2016</year>
 </pub-date>
 <volume>27</volume>
 <issue>1</issue>
 <fpage>25</fpage>
 <lpage>39</lpage>
 ...
</article-meta>
...