Scientific and Technical Information Branch, and Division of Public Affairs, National Aeronautics and Space Administration : for sale by the Supt. of Docs., U.S. Govt. Print. Off.1979.<NC161-171>
Scientific and Technical Information Branch, and Division of Public Affairs, National Aeronautics and Space Administration : for sale by the Supt. of Docs., U.S. Govt. Print. Off.1979.<NC161-A34>