About: http://webisa.webdatacommons.org/417377360

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	An additional acknowledgment which may be flagged in the header is a notification to the sender that the message has been printed, i.e., a print receipt, and/or that the message has been deleted either manually or automatically.
http://www.w3.org/ns/prov#wasQuotedFrom	google.com