Bendix, Reinhard, author
University of California Press, 1974
Buku Teks
Beach, Dale S., author
Macmillan, 1975
Buku Teks
edited by Robert Teviot Livingston and Stanley H. Milberg
Colombia University Press , 1957
Buku Teks
Jenks, James M.
New Jersey : Alexander Hamilton Institute, Inc,
Buku Referensi
Chruden, Herbert J., author
South-Western, 1966
Buku Teks