About: http://webisa.webdatacommons.org/220451986

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	Sometimes null is an error (i.e. it must not ever be set), sometimes it means unknown, sometimes it means not yet set, ...
http://www.w3.org/ns/prov#wasQuotedFrom	stackoverflow.com