About: http://webisa.webdatacommons.org/283670132

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	There is no point in testing whether x or y is null, because when null is passed, IsNumber() returns false.
http://www.w3.org/ns/prov#wasQuotedFrom	stackexchange.com