Matz, Adolph
Ohio South-Western Publishing , 1967/1991
Buku Teks
Hansen, Don R.
South-Western College, 2000
Buku Teks
Hansen, Don R.
South-Western College Publishing, 1997
Buku Teks
Usry, Milton F.
South Western, 1988
Buku Teks
Gillespie, Cecil
Prentice-Hall, 1957
Buku Teks