PropertyValue
http://www.w3.org/1999/02/22-rdf-syntax-ns#type
http://www.w3.org/ns/prov#value
  • The scientific problem these institutions and the scientists working for them confronted was extraordinarily difficult, especially given the problems and costs of observation and the relatively undeveloped state of ecological theory at that time.
http://www.w3.org/ns/prov#wasQuotedFrom
  • nap.edu