Cornick, Tim
E & FN Spon, 1996
Buku Teks
Flores, Ivan, author
Prentice-Hall, 1967
Buku Teks
Novitski, B. J., author
Rockport Publishers, 1998
Buku Teks
Wilson, Charles E., author
Prentice-Hall, 1997
Buku Teks
Bartee, Thomas C., author
McGraw-Hill, 1991
Buku Teks