Model

<!ENTITY % struct-title-elements
                        "| %all-phrase; | %break.class; |
                         %citation.class;"                           >

Expanded Model

| email | ext-link | uri | inline-supplementary-material | related-article | related-object | hr | bold | fixed-case | italic | monospace | overline | overline-start | overline-end | roman | sans-serif | sc | strike | underline | underline-start | underline-end | ruby | alternatives | inline-graphic | inline-media | private-char | chem-struct | inline-formula | tex-math | mml:math | abbrev | index-term | index-term-range-end | milestone-end | milestone-start | named-content | styled-content | fn | target | xref | sub | sup | x | break | citation-alternatives | element-citation | mixed-citation | nlm-citation