About: http://webisa.webdatacommons.org/419278979

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	During the Cold war, German secret police used cerium oxalate to write hidden messages and used a solution of manganese sulfate, hydrogen peroxide and other chemicals to reveal the texts.
http://www.w3.org/ns/prov#wasQuotedFrom	wisegeek.com