curated set of RDF prefixes

 RDF::NS::Curated contains a limited list of prefix and URI pairs that
 are commonly used in RDF. The intention is that prefixes in this list
 can be safely used in code that has a long lifetime. The list has been
 derived mostly from W3C standards documents, but also some popularity
 lists.
 .
 Resource Description Framework (RDF) is a standard model for data
 interchange on the Web.