About: http://webisa.webdatacommons.org/415473057

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	For waves that propagate in a medium, such as sound waves, the velocity of the observer and of the source are relative to the medium in which the waves are transmitted.
http://www.w3.org/ns/prov#wasQuotedFrom	wikipedia.org