%references.class; Reference Elements (Bibliographic Citation) Class Elements

A block of elements, originally defined to be used within a reference citation inside a bibliographic reference list (<element-citation> or <mixed-citation>), but that have other uses as a class.
Declaration
<!ENTITY % references.class
                        "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"  >