Comment in a Citation


Used to mark unstructured text within an otherwise element-structured bibliographic reference (<nlm-citation>); it is therefore not necessarily a comment in the formal sense of commentary. In an unstructured bibliographic reference, this text would merely be a mixture of text, numbers, or special characters, such as punctuation, and not marked with tags at all.


Because the model for <citation> is a loose model with data characters allowed everywhere, this element will rarely be needed in <citation>s.

The element <comment> is used to contain additional information about a citation that is not appropriate in any of the other, named, information types. For extensive examples of formatted <nlm-citation>s including use of <comment>s in <nlm-citation>s, see: Sample PubMed Central Citations. To see tagged versions of these example, see: Sample PubMed Central Citations - XML Tagged.

The <comment> element is used in <citation>s largely for the sake of conversion, to preserve unusual bits of semantic markup when translating from other DTDs. Typical comments might include:

 <comment>translated from Russian</comment>

Conversion Note: The <comment> element should be used to mark substantive text only; it should not be used to mark punctuation that occurs between elements.

Related Elements

Display Note: <comment>s should appear inline with other reference elements. This is a very different rendering from that given the similar element <annotation>, which is typically a longer commentary concerning a citation and is therefore rendered as a block element.

Model Information

Content Model

<!ELEMENT  comment      (#PCDATA %comment-elements;)*                >


Any combination of:

This element may be contained in:

<citation> Citation; <nlm-citation> NLM Citation Model; <product> Product Information; <related-article> Related Article Information

Tagged Example

<nlm-citation citation-type="book">
<person-group person-group-type="author">
<source>AIDS, agencies and drug abuse: the Edinburgh experience</source>
<publisher-loc>Norwich (England)</publisher-loc>
<publisher-name>Social Works Monographs</publisher-name>
<comment>Revised version of a dissertation originally submitted as part 
of an MSc. in applied social studies at Oxford University</comment>