Entity: compound-subject-part-elements

Content Model

| 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 |
                         named-content | styled-content | sub | sup