PropertyValue
http://www.w3.org/1999/02/22-rdf-syntax-ns#type
http://www.w3.org/ns/prov#value
  • The warming of the Earth is widely attributed to three things: natural, long-term climate variation; alterations to the landscape such as spreading cities and forest clearing, and a buildup of heat-trapping gases ??? primarily carbon dioxide, methane and water vapor, known as ???greenhouse gases??? ??? in the atmosphere.
http://www.w3.org/ns/prov#wasQuotedFrom
  • realclimate.org