Foundation for Rural Education and Development (FRED) (June 12, 1999, 1999
Buku Teks
Hughes, Fredrick W., author
Prentice-Hall, 1983
Buku Referensi
Megginson, William L., author
McGraw-Hill, 2000
Buku Referensi
Byrd, Mary Jane
mcGraw-Hill , 2000
Multimedia
Tracton, Ken
G/L Tab Books, 1975
Buku Teks