About: http://webisa.webdatacommons.org/77004532

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	Trying to minimize surprises for anyone reading your code is a very good thing to do, and returning a reference from operator= goes well with that philosophy.
http://www.w3.org/ns/prov#wasQuotedFrom	gamedev.net