Ali Farazmand
CRC press, 2009
Buku Teks
edited by Robert T. Golembiewski, Frank Gibson, Geoffrey Y. Cornog
Rand McNally College, 1972
Buku Teks
Pfiffner, John M., author
Ronald Press, 1960
Buku Teks
Denhardt, Robert B., author
Harcourt College, 1999
Buku Teks
Appleby, Paul H., author
University of Alabama, 1949
Buku Teks