http://www.nanopub.org/nschema#hasAssertion
http://www.nanopub.org/nschema#hasProvenance
http://www.nanopub.org/nschema#hasPublicationInfo
http://www.w3.org/ns/prov#generatedAtTime
http://www.w3.org/ns/prov#wasAttributedTo
http://www.w3.org/1999/02/22-rdf-syntax-ns#type