About: http://webisa.webdatacommons.org/293222224

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	rare earth elements such as Lanthanum or Cerium which were intentionally included in the optical glass.
http://www.w3.org/ns/prov#wasQuotedFrom	earthlink.net