Manned Spacecraft Center (U.S.) & United States. National Aeronautics and Space Administration. (1970). Earth resources program: Synopsis of activity. The Center.
Lua i Stíl Chicago (17ú heag.)Manned Spacecraft Center (U.S.) agus United States. National Aeronautics and Space Administration. Earth Resources Program: Synopsis of Activity. Houston: The Center, 1970.
Lua MLA (8ú heag.)Manned Spacecraft Center (U.S.) agus United States. National Aeronautics and Space Administration. Earth Resources Program: Synopsis of Activity. The Center, 1970.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.