Bonner, Thomas Neville, author
Prentice-Hall, 1963
Buku Teks
edited by Jack A. Goldstone, Ted Robert Gurr, Farrokh Moshiri
Westview Press, 1991
Buku Teks
Varga, Eugen, 1879-1964, author
Foreign Languages Publishing House, 1961
Buku Teks
Kohn, Hans, author
D. Van Nostrand, 1965
Buku Teks
Urwick, Lyndall F., author
Pitman Publishing Corporation , 1958
Buku Teks