BITS 2.0
( #PCDATA | email | ext-link | uri | bold | fixed-case | italic | monospace | overline
| overline-start | overline-end | roman | sans-serif | sc | serif | strike | underline
| underline-start | underline-end | ruby | named-content | styled-content | sub |
sup )*
BITS 2.1
( #PCDATA | email | ext-link | uri | inline-graphic | inline-media | private-char
| bold | fixed-case | italic | monospace | overline | overline-start | overline-end
| roman | sans-serif | sc | serif | strike | underline | underline-start | underline-end
| ruby | named-content | styled-content | sub | sup )*