About: http://webisa.webdatacommons.org/146205386

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	You don???t even have to pass a variant to the generator (although, you certainly can), any attribute compatible with any of the types of the alternatives can be used, causing the corresponding formatting expression to be chosen.
http://www.w3.org/ns/prov#wasQuotedFrom	boost-spirit.com