About: http://webisa.webdatacommons.org/423421218

Property	Value
http://www.w3.org/1999/02/22-rdf-syntax-ns#type	http://www.w3.org/ns/prov#Entity
http://www.w3.org/ns/prov#value	Which, to me, implies that the operands could be either literals or other types of expressions.
http://www.w3.org/ns/prov#wasQuotedFrom	digitalmars.com