Commons, John R.
University of Madison Press , 1959
Buku Teks
McManis, Charles R., author
Thomson , 2004
Buku Teks
edited by A. James Casner
Little, Brown, 1952
Buku Teks
Cunningham, Roger A., author
West Pub., 1993
Buku Teks
Casner, A. James, author
Little, Brown and Company, 1969
Buku Teks