About: http://webisa.webdatacommons.org/39421625

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	Because reference types cannot be null, you must correct the error by either removing the Null property or by setting the Null property value to No.ExampleThe following code generates this warning:
http://www.w3.org/ns/prov#wasQuotedFrom	microsoft.com