About: http://webisa.webdatacommons.org/199164711

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	For this reason, signing fields present in the message such as Date, Subject, Reply-To, Sender, and all MIME header fields are highly advised.
http://www.w3.org/ns/prov#wasQuotedFrom	blogspot.com