About: http://webisa.webdatacommons.org/231270404

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	Petroleum feedstocks are characterized by relatively high levels of contaminants, including sulfur, nitrogen, Conradson carbon residue, aromatic compounds and metals such as nickel, vanadium and iron.
http://www.w3.org/ns/prov#wasQuotedFrom	google.es