Fishers, David A.
West Publishing Company, 1994
Buku Teks
Phillips, Jerry J.
West Publishing Company, 1993
Buku Teks
Owen, G David
West Publishing, 2008
Buku Teks
Moore, William L.
Hill Book , 1993
Buku Teks
edited by Dennis J. Cada and Timothy R. Covington
Facts & Comparisons, 2002
Buku Teks