About: http://webisa.webdatacommons.org/274997262

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	R21 can be a variety of groups such as halogen, hydroxyl, thio, amino, (C1-C6)alkoxy, (C1-C6)alkylthio, (C1-C6)acyloxy, (C1-C6)alkylamino, di(C1-C6)alkylamino, or a heterocyclic group.
http://www.w3.org/ns/prov#wasQuotedFrom	google.com