compiled and edited by William L. Langer
Houghton Mifflin, 1968
Buku Referensi
Asimov, Isaac, author
Doubleday, 1964
Buku Referensi
edited by. Richard Garnett
Delhi, India Akashdeep 1992
Buku Referensi
C.S. Hammond & Company
C.S. Hammond & Company, 1958
Buku Teks
Esposito, John L., author
New York : Oxford University Press, 1995,
Buku Referensi