About: http://webisa.webdatacommons.org/191722366

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	Trace Metals - Metals, including nickel, iron, and vanadium are often found in crude oils in small quantities and are removed during the refining process.
http://www.w3.org/ns/prov#wasQuotedFrom	setlaboratories.com