Não informado. (1961). Satellite situation report. National Aeronautics and Space Administration, Goddard Space Flight Center.
Chicago-referens (17:e uppl.)Não informado. Satellite Situation Report. Greenbelt, Md: National Aeronautics and Space Administration, Goddard Space Flight Center, 1961.
MLA-referens (8:e uppl.)Não informado. Satellite Situation Report. National Aeronautics and Space Administration, Goddard Space Flight Center, 1961.
Varning: dessa hänvisningar är inte alltid fullständigt riktiga.