BITS 0.2
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| roman | sans-serif | sc | strike | underline | underline-start | underline-end |
alternatives | inline-graphic | private-char | chem-struct | inline-formula | label
| tex-math | mml:math | abbrev | index-term | index-term-range-end | milestone-end
| milestone-start | named-content | styled-content | price | annotation | article-title
| chapter-title | collab | collab-alternatives | comment | conf-date | conf-loc |
conf-name | conf-sponsor | date | date-in-citation | day | edition | email | elocation-id
| etal | ext-link | fpage | gov | institution | isbn | issn | issn-l | issue | issue-id
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BITS 1.0
( #PCDATA | inline-supplementary-material | related-article | related-object | hr
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| inline-formula | label | tex-math | mml:math | abbrev | index-term | index-term-range-end
| milestone-end | milestone-start | named-content | styled-content | price | annotation
| article-title | chapter-title | collab | collab-alternatives | comment | conf-date
| conf-loc | conf-name | conf-sponsor | date | date-in-citation | day | edition |
email | elocation-id | etal | ext-link | fpage | gov | institution | institution-wrap
| isbn | issn | issn-l | issue | issue-id | issue-part | issue-title | lpage | month
| name | name-alternatives | object-id | page-range | part-title | patent | person-group
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BITS 2.0
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| inline-formula | label | tex-math | mml:math | abbrev | index-term | index-term-range-end
| milestone-end | milestone-start | named-content | styled-content | price | annotation
| article-title | chapter-title | collab | collab-alternatives | comment | conf-acronym
| conf-date | conf-loc | conf-name | conf-sponsor | data-title | date | date-in-citation
| day | edition | email | elocation-id | etal | ext-link | fpage | gov | institution
| institution-wrap | isbn | issn | issn-l | issue | issue-id | issue-part | issue-title
| lpage | month | name | name-alternatives | object-id | page-range | part-title |
patent | person-group | pub-id | publisher-loc | publisher-name | role | season |
series | size | source | std | string-name | supplement | trans-source | trans-title
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sub | sup | x )*
BITS 2.1
( #PCDATA | inline-supplementary-material | related-article | related-object | hr
| break | 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 | label | tex-math | mml:math | abbrev | index-term | index-term-range-end
| milestone-end | milestone-start | named-content | styled-content | price | annotation
| article-title | chapter-title | collab | collab-alternatives | comment | conf-acronym
| conf-date | conf-loc | conf-name | conf-sponsor | data-title | date | date-in-citation
| day | edition | email | elocation-id | etal | ext-link | fpage | gov | institution
| institution-wrap | isbn | issn | issn-l | issue | issue-id | issue-part | issue-title
| lpage | month | name | name-alternatives | object-id | page-range | part-title |
patent | person-group | pub-id | publisher-loc | publisher-name | role | season |
series | size | source | std | string-date | string-name | supplement | trans-source
| trans-title | uri | version | volume | volume-id | volume-series | year | fn | target
| xref | sub | sup | x )*