PropertyValue
http://www.w3.org/1999/02/22-rdf-syntax-ns#type
http://www.w3.org/ns/prov#value
  • There are 25 known radioactive isotopes of lead, some of which occur naturally in small amounts.Natural Occurrence and ProcessingAlthough lead is seldom found uncombined in nature, its compounds are widely distributed throughout the world, principally in the ores galena, cerussite, and anglesite.
http://www.w3.org/ns/prov#wasQuotedFrom
  • reference.com