Two Citation Styles

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This Tag Set allows citations to be tagged in two markedly different ways. Neither is superior to the other in supporting searching or making the citations into live links. Neither is inherently more semantically detailed than the other. One, the “mixed” style, mixes tags and text inside the citation content, and thus can preserve more closely the element order, punctuation, and spacing found in an original printed document or created editorially. The other, the “element” style, has only element content and does not contain any untagged text, which makes it possible to regularize the punctuation for references across a publication, publisher’s content management system, or archive’s content. It also requires that spacing and punctuation be created in formatting the content for display.

Mixed Style Citations

The “mixed” style is named because its content is what XML calls “mixed content”, a mixture of text and embedded elements. In this style, the citation is captured exactly as it was found in the print, complete with punctuation marks, line breaks, spaces, etc. It would be possible to tag a citation with just the <mixed-citation> element and text inside, though this is not Best practice.

<mixed-citation>Petitti DB, Crooks VC, Buckwalter JG, Chiu V. Blood 
 pressure levels before dementia. Arch Neurol. 2005 Jan; 62 (1): 
 112&ndash;116.</mixed-citation>

Although this Tag Set does not enforce it, Best practice is to tag as many of the following elements as possible within a citation to a journal article, so that PubMed Central, Crossref, or other matching services can make the journal citation into a live link:

<article-title>
<source> (journal title)
<volume> (volume number)
<fpage> (first page of the article)
<lpage> (last page of the article)
<name> (at least the surname of the primary author)
Publication date (using one or more of the date elements such as <year>, <month>, and <day>)

In order to make a citation into a live link, as much of this author and date information as is available should be preserved, even if it is not possible to tag all the elements just named. The most important date tag is <year>, and it should always be tagged if possible, for example, <year>2003</year>. The <day>, <month>, and <season> elements are used more rarely; they are provided because some of the citation matching services can use the month and day information if it is available.

The simple citation we just examined would more properly be tagged with the name of the first author, the publication data (issue and volume), and the year of publication:

<mixed-citation publication-type="journal"><string-name><surname>Petitti</surname>  <given-names>DB</given-names>
 </string-name>, Crooks VC, Buckwalter JG, Chiu V. <article-title>Blood pressure levels before dementia</article-title>. <source>Arch Neurol</source>. 
 <year iso-8601-date="2005">2005</year> Jan;<volume>62</volume>(<issue>1</issue>): 
 <fpage>112</fpage>&ndash;116.</mixed-citation>

Best practice, however, is to tag as many of the author and publication details as possible for retrieval and linking purposes:

<mixed-citation publication-type="journal" publication-format="print">
 <string-name><surname>Petitti</surname> <given-names>DB</given-names> 
 </string-name>, <string-name><surname>Crooks</surname>
 <given-names>VC</given-names></string-name>, 
 <string-name><surname>Buckwalter</surname> <given-names>JG</given-names>
 </string-name>, <string-name><surname>Chiu</surname> <given-names>V</given-names>
 </string-name>. <article-title>Blood pressure levels before dementia</article-title>.
 <source>Arch Neurol</source>. <year iso-8601-date="2005-01">2005</year> 
 <month>Jan</month>;<volume>62</volume>(<issue>1</issue>):
 <fpage>112</fpage>&ndash;<lpage>116</lpage>.</mixed-citation>

Element Style Citations

The “element” style is named for its element content, as it is referred to in XML. Element content, unlike mixed content, does not include any text interspersed with the elements. In this model, any text that would not be separately tagged in a <mixed-citation> can be wrapped in a <comment> element, thus ensuring that all text is enclosed in tags. All punctuation marks, line breaks, spaces, etc. are removed from the tagged citation and must be replaced programmatically to view the citation in display or print. Also, there is the possibility that the display of existing content converted to element-style citations will not match the display of the same citations in their source documents. This is the style used to regularize the appearance of citations. Displaying this style of citation requires more complex output processing and means that all parts of the citation need to be tagged.

<article-title>
<source> (journal title)
<volume> (volume number)
<fpage> (first page of the article)
<lpage> (last page of the article)
<name> (at least the surname of the primary author)
Publication date (using one or more of the date elements such as <year>, <month>, and <day>)

So the citation we just examined would be tagged as an element-style citation as follows:

<element-citation publication-type="journal" publication-format="print">
 <name><surname>Petitti</surname><given-names>DB</given-names></name>
 <name><surname>Crooks</surname><given-names>VC</given-names></name>
 <name><surname>Buckwalter</surname><given-names>JG</given-names></name>
 <name><surname>Chiu</surname><given-names>V</given-names></name>
 <article-title>Blood pressure levels before dementia</article-title>
 <source>Arch Neurol</source>
 <year iso-8601-date="2005-01">2005</year>
 <month>Jan</month>
 <volume>62</volume>
 <issue>1</issue>
 <fpage>112</fpage>
 <lpage>116</lpage>
</element-citation>