Attribute list for the cross-reference element (<xref>)
<!ENTITY % xref-atts "id ID #IMPLIED ref-type (%ref-types;) #IMPLIED rid IDREFS #IMPLIED" >
id ID #IMPLIED ref-type (aff | app | author-notes | bibr | book-part | boxed-text | chem | contrib | corresp | disp-formula | fig | fn | glossary | kwd | list | plate | scheme | sec | statement | supplementary-material | table | table-fn | other) #IMPLIED rid IDREFS #IMPLIED
link3.ent