BITS 0.2
( #PCDATA | addr-line | country | fax | institution | phone | email | ext-link | uri
| inline-supplementary-material | related-article | related-object | hr | bold | italic
| monospace | overline | overline-start | overline-end | roman | sans-serif | sc |
strike | underline | underline-start | underline-end | alternatives | inline-graphic
| 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 | label )*
BITS 1.0
( #PCDATA | addr-line | country | fax | institution | institution-wrap | phone | 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 | 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 | label )*
BITS 2.0
( #PCDATA | addr-line | city | country | fax | institution | institution-wrap | phone
| postal-code | state | 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 | serif | strike | underline | underline-start
| underline-end | ruby | alternatives | inline-graphic | 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 | label )*
BITS 2.1
( #PCDATA | addr-line | city | country | fax | institution | institution-wrap | phone
| postal-code | state | 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 | serif | 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 | label )*