Bahl, B.S., author
S Chand & Company, 1997
Buku Teks
Boxer, Robert J., author
McGraw-Hill, 1998
Buku Referensi
Bahl, B.S., author
S. Chand, 1985
Buku Teks
Hecht, Harry G.
Prentice-Hall, 1990
Buku Teks
Bergamini, David, author
Time Incorporated, 1963
Buku Referensi