William A. Lovett, author
West Publishing, 1992
Buku Teks
William A. Lovett, author
West Publishing, 1997
Buku Teks
Hales, Michael G.
Prentice-Hall, 1989.
Buku Teks
Schroeder, Milton R., author
Warren, Gorham & Lamont, 1995
Buku Teks
West Publishing, 1991
Buku Teks