Content model for the <disp-formula> element.
<!ENTITY % disp-formula-model
"(#PCDATA %disp-formula-elements;)*" >(#PCDATA | alt-text | long-desc | abstract | email | ext-link | uri | break | bold | fixed-case | italic | monospace | overline | roman | sans-serif | sc | strike | underline | ruby | inline-graphic | private-char | chem-struct | inline-formula | kwd-group | label | named-content | styled-content | tex-math | mml:math | alternatives | array | code | graphic | media | preformat | sub | sup)*
JATS-math1.ent