About: http://webisa.webdatacommons.org/209990880

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	// this copy constructor is an optimization: we do not need to copy the storage_ member,
http://www.w3.org/ns/prov#wasQuotedFrom	boost.org