About: http://webisa.webdatacommons.org/384080701

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	These systems use either one or two pipes, and heat water through a variety of methods such as electricity, oil, or natural gas.
http://www.w3.org/ns/prov#wasQuotedFrom	wisegeek.com