About: http://webisa.webdatacommons.org/113260654

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	This problem occurs when there is a link created from an optional field in the source schema to a destination field.
http://www.w3.org/ns/prov#wasQuotedFrom	microsoft.com