Asimov, Isaac, author
Greenwood Press , 1979
Buku Teks
Berlin Kunftwiffenchaft 1939
Buku Teks
Asimov, Isaac, author
Faweett World Library , 1967
Buku Teks
edited by Martin H. Greenberg
Grafton, 1991
Buku Teks
Otto Soemarwoto, author
Djambatan, 2001
Buku Teks