About: http://webisa.webdatacommons.org/326866758

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	That means, when the argument is a pointer to object (NSData *), you need to give it a pointer to pointer (NSData **). [NSData dataWithBytes:... is not what you need to pass; you need to pass a pointer to that.
http://www.w3.org/ns/prov#wasQuotedFrom	stackoverflow.com