About: http://webisa.webdatacommons.org/158960514

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	The test you linked to is interesting, and Yannis Rizos's answer is great, but I think what is also important is this:
http://www.w3.org/ns/prov#wasQuotedFrom	stackexchange.com