About: http://webisa.webdatacommons.org/90227141

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	In Structure I, Ar1 is a tetravalent aromatic group or a tetravalent heterocyclic group, or mixtures thereof.
http://www.w3.org/ns/prov#wasQuotedFrom	google.com