PropertyValue
http://www.w3.org/1999/02/22-rdf-syntax-ns#type
http://www.w3.org/ns/prov#value
  • The U.S. EPA estimates the aggregate amount of human-related sources of such methane emissions are 70 percent of the total and are over 30 million tons of methane emitted annually in the U.S., causing global warming and other environmental problems.
http://www.w3.org/ns/prov#wasQuotedFrom
  • google.com