Followup on the meta stuff. Atom has a nice category element where you
can attach a uri to designate a schema. So I think we’ll understand a
default uri of “” or some
such, and then just use the SKOS RDF vocab to define it in localized
ways. See here:

An example:

<skos:Concept rdf:ID="psychology">
   <skos:prefLabel xml:lang="en">psychology</skos:prefLabel>
   <skos:broader rdf:resource="life_science"/>
   <skos:broader rdf:resource="social_science"/>

So for APA, you’d just do:

… and tools could grab additional info from the RDF files if needed.