About: http://webisa.webdatacommons.org/263061522

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	Firstly the convention is that a subroutine will return undef if there is an error, so that you can write
http://www.w3.org/ns/prov#wasQuotedFrom	stackoverflow.com