BITS 0.2
( #PCDATA | day | month | season | year | bold | italic | monospace | overline | overline-start
| overline-end | roman | sans-serif | sc | strike | underline | underline-start |
underline-end | x )*
BITS 1.0
( #PCDATA | day | era | month | season | year | bold | fixed-case | italic | monospace
| overline | overline-start | overline-end | roman | sans-serif | sc | strike | underline
| underline-start | underline-end | ruby | x )*
BITS 2.0
( #PCDATA | day | era | month | season | year | bold | fixed-case | italic | monospace
| overline | overline-start | overline-end | roman | sans-serif | sc | serif | strike
| underline | underline-start | underline-end | ruby | x )*
BITS 2.1
( #PCDATA | day | era | month | season | year | bold | fixed-case | italic | monospace
| overline | overline-start | overline-end | roman | sans-serif | sc | serif | strike
| underline | underline-start | underline-end | ruby | sub | sup | x )*