Averill, Lawrence H.
West Publishing Company, 1978
Buku Teks
West Publishing Company, 1996
Buku Teks
Whaley, Douglas J.
Harcourt Brace & Company, 1992
Buku Teks
Braucher, Robert, author
Foundation Press, 1964
Buku Teks
Brook, James
Little, Brown , 1994
Buku Teks