About: http://webisa.webdatacommons.org/43452637

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	X is --O--, --S-- or --N(R8)-, where R8 is a hydrogen atom or an alkyl group;
http://www.w3.org/ns/prov#wasQuotedFrom	google.com