Content Model

<!ENTITY % textual-form-elements
                        "| %emphasis.class; |
                         %inline-display-noalt.class; |
                         %math.class; |
                         %phrase-content.class; | %subsup.class;"    >

Expanded Content Model

| bold | italic | monospace | overline | roman | sans-serif | sc | strike | underline | inline-graphic | private-char | tex-math | mml:math | named-content | styled-content | sub | sup