About: http://webisa.webdatacommons.org/44895581

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	However, the same sort of issue occurs if the provider explicitly labels the object but does not include one you want (that the object does support.) So better then optional would be guarantee signatures.
http://www.w3.org/ns/prov#wasQuotedFrom	osnews.com