Ransone, Coleman B.
University of Alabama Press, 1956
Buku Teks
Jones, Joseph Marion
Macmillan, 1944
Buku Teks
Harper and Brothers, 1953
Buku Teks
Tribe, Laurence H., author
Foundation Press, 1979
Buku Teks
Pritchett, C. Herman, author
McGraw-Hill, 1981
Buku Teks