About: http://webisa.webdatacommons.org/17039218

Property	Value
http://www.w3.org/1999/02/22-rdf-syntax-ns#type	http://www.w3.org/ns/prov#Entity
http://www.w3.org/ns/prov#value	In this case, it says that anything that is going to call itself a kind of missile, must have a setDestination method. the virtual keyword just means that the implementation of a function will be determined at run-time.
http://www.w3.org/ns/prov#wasQuotedFrom	daniweb.com