awol:PlainText
http://bblfish.net/work/atom-owl/2006-06-06/#PlainText
rdfs:comment
http://www.w3.org/2000/01/rdf-schema#comment
see §3.1.1.1 of rfc 4287. The ...... ss of all plain text literals.
@en
graph:default
https://triplydb.com/sun/awol/graphs/default