A container element that holds unstructured text within an otherwise element-structured bibliographic reference (<citation> or <nlm-citation>); therefore, this is not necessarily a comment in the formal sense of commentary. In an unstructured bibliographic reference, this textual material would merely be a mixture of text, numbers, or special characters, such as punctuation, and not marked with tags at all.
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.
Since in the Journal Archiving Tag Set, the model for <citation> is a loose model with text, numbers, and special characters, such as punctuation, allowed everywhere, this element will rarely be needed. The <comment> element has been defined here largely for the sake of conversion, to preserve unusual bits of semantic markup when translating from other DTDs and schemas. Typical comments might include:
<comment>[Abstract]</comment> <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.
<!ELEMENT comment (#PCDATA %comment-elements;)* >
Any combination of:
No sample is available at this time.