att.canonical

att.canonical provides attributes which can be used to associate a representation such as a name or title with canonical information about the object being named or referenced.
Moduletei — 1 The TEI Infrastructure
Members att.naming [ att.personal [ addName forename genName orgName persName roleName surname] affiliation birth bloc climate collection country death district education event geogFeat geogName institution name nationality occupation placeName population pubPlace region relation repository residence rs settlement socecStatus state terrain trait] author docAuthor docTitle resp title
AttributesIn addition to global attributes
keyprovides an externally-defined means of identifying the entity (or entities) being named, using a coded value of some kind.
Status Optional
Datatype 

<rng:ref name="data.key"/>
data.key
Values any string of Unicode characters
Note
The value may be a unique identifier from a database, or any other externally-defined string identifying the referent.
ref (reference) provides an explicit means of locating a full definition for the entity being named by means of one or more URIs.
Status Optional
Datatype 1–∞ occurrences of 

<rng:ref name="data.pointer"/>
data.pointer
separated by whitespace
Note
The value must point directly to one or more XML elements by means of one or more URIs, separated by whitespace. If more than one is supplied, the implication is that the name identifies several distinct entities.