Fraser, Lyn M.
Prentice-Hall International, 1995
Buku Teks
Foster, Louis O.
Chelton, 1961
Buku Teks
by Joseph T. Straub
Gemini Books, 2000
Buku Referensi
Budd, Thomas A.
Alexander Hamilton Institute, 1961
Buku Teks
Fraser, Lyn M.
Prentice-Hall, 1998
Buku Teks