About: http://webisa.webdatacommons.org/452700022

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	This list of manned Mars mission plans in the 20th century is a listing of formal proposals, studies, and plans for a human manned mission to Mars during the 20th century.
http://www.w3.org/ns/prov#wasQuotedFrom	wikipedia.org