Issue number of a journal which contains the related article.
The @issue attribute can be used, along with the @vol, @journal-id, and @page attributes, to provide the metadata for the related article.
The issue number in which the primary journal article has been published is given in the <issue> element, which is part of the article metadata. This attribute is for related articles.
|Data characters||Text, numbers, or special characters.|
|Restriction: This attribute may be specified if the element is used.|