PropertyValue
http://www.w3.org/1999/02/22-rdf-syntax-ns#type
http://www.w3.org/ns/prov#value
  • Internet calling program Skype, which launched in 2003 and now has millions of users, is similar to chat clients such as AIM or Yahoo Messenger.
http://www.w3.org/ns/prov#wasQuotedFrom
  • phys.org