Heintz, James A.
South-Western Publishing, 1990
Buku Teks
Carlson, Arthur E.
South Western, 1986
Buku Teks
Heintz, James A.
Thomson/South-Wester, 2005.
Buku Teks
Heintz, James A.
South-Western , 2005
Buku Teks
Carlson, Arthur E.
South-Western Publishing , 1982
Buku Teks