a.external.ptr()

Contenu	( @entityref="{ENTITY}" ? , @xpointer ? , simpleLink (►( @xlink:type="simple"="simple" ? , @xlink:href="{anyURI}" ? , @href="{anyURI}" ? , @xlink:role="{anyURI}" ? , @xlink:arcrole="{anyURI}" ? , @xlink:title ? , @xlink:show="( new | replace | embed | other | none )" ? , @xlink:actuate="( onLoad | onRequest | other | none )" ?  )) )
Usage	A. <archref>  B. <bibref>  D. <dao>, <daoloc>  E. <extptr>, <extptrloc>, <extref>, <extrefloc>  T. <title>