BITS 1.0
( #PCDATA | email | ext-link | uri | bold | fixed-case | italic | monospace | overline
| overline-start | overline-end | roman | sans-serif | sc | strike | underline | underline-start
| underline-end | ruby | abbrev | index-term | index-term-range-end | milestone-end
| milestone-start | named-content | styled-content | fn | target | xref | sub | sup
)*
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 | abbrev | index-term | index-term-range-end
| milestone-end | milestone-start | named-content | styled-content | fn | target |
xref | sub | sup )*
BITS 2.1
( #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 | inline-graphic | inline-media | private-char
| abbrev | index-term | index-term-range-end | milestone-end | milestone-start | named-content
| styled-content | fn | target | xref | sub | sup )*