Related Essay: For a discussion on the use of <kwd-group>, see Keywords.
Usage: A document may take multiple sets of keywords, with the @kwd-group-type, @specific-use, or @xml:lang attributes used to discriminate between them. The <kwd> element does not take the @xml:lang attribute; that is reserved for the <kwd-group>. This means that keywords must be sorted by language and entered in language groups.
The @kwd-group-type attribute most commonly names the source of the keywords, such as “MESH”, “ISO-463”, or “author-generated”. But it is also appropriate to use @kwd-group-type to record the type of keywords, for example, “hierarchical” for keywords that are grouped into a hierarchy, “abbreviations” for keywords that contain an abbreviation and its expansion, or “code” for keywords that contain a code and its text but where the source of the codes is unknown.
<!ELEMENT kwd-group %kwd-group-model; >
Expanded Content Model
(title?, (kwd | compound-kwd | nested-kwd)+)
This element may be contained in:
An author’s list of keywords for a document:
<article dtd-version="1.1"> <front> <article-meta>... <abstract>...</abstract> <kwd-group kwd-group-type="author"> <kwd>DNA analysis</kwd> <kwd>gene expression</kwd> <kwd>parallel cloning</kwd> <kwd>fluid microarray</kwd> </kwd-group> </article-meta> </front> ...</article>
Keyword group with compound keywords:
... <kwd-group> <compound-kwd> <compound-kwd-part content-type="code">B01D57/02</compound-kwd-part> <compound-kwd-part content-type="value">By electrophoresis</compound-kwd-part> </compound-kwd> ... </kwd-group> ...
Multiple keyword groups for a document (including Japanese):
... <article-meta>... <kwd-group xml:lang="en"> <kwd>heated air</kwd> </kwd-group> <kwd-group xml:lang="ja"> <kwd>加温空気</kwd> </kwd-group> ... </article-meta> ...