About: http://webisa.webdatacommons.org/17322827

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	Since this is exploding, I am guessing that user is a column that does not exist, either because a) it is not defined in a migration or b) you didn't run the migration.
http://www.w3.org/ns/prov#wasQuotedFrom	stackoverflow.com