A grouping element to hold related volume and issue elements
The following, in order:
<volume> Volume Number, zero or more
<volume-id> Volume Identifier, zero or more
<volume-series> Volume Series, zero or one
<issue> Issue Number, zero or more
<issue-id> Issue Identifier, zero or more
<issue-title> Issue Title, zero or more
<issue-sponsor> Issue Sponsor, zero or more
<issue-part> Issue Part, zero or one