About: http://webisa.webdatacommons.org/9201832

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	Instead of specifying a named item for attribute columns, you can specify $n or $-n, where n is an integer that indicates the item's row position.
http://www.w3.org/ns/prov#wasQuotedFrom	oracle.com