Model for the <issue-part> element.
A publisher may split an issue into two or more separately bound or separately issued parts. This element holds the identifiers (titles, part numbers, etc.) for those publishing components.
<!ENTITY % issue-part-elements "%just-rendition;" >
| email | ext-link | uri | inline-supplementary-material | related-article | related-object | hr | bold | italic | monospace | overline | overline-start | overline-end | roman | sans-serif | sc | strike | underline | underline-start | underline-end | alternatives | inline-graphic | private-char | chem-struct | inline-formula | tex-math | mml:math | abbrev | milestone-end | milestone-start | named-content | styled-content | fn | target | xref | sub | sup | x