Administrator, NASA Content (2015-03-03). "The Pioneer Missions". NASA (به انگلیسی). Archived from the original on 15 August 2011. Retrieved 2021-11-16.
Administrator, NASA Content (2015-03-03). "The Pioneer Missions". NASA (به انگلیسی). Archived from the original on 15 August 2011. Retrieved 2021-11-16.