About: http://webisa.webdatacommons.org/401766002

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	That is, there is a precedent for extending a relational-calculus query with a relational-algebra expression, although such extensions have been thus far restricted to variations of JOIN operations.
http://www.w3.org/ns/prov#wasQuotedFrom	google.com