Beus, J. G. De
The future of the west / J. G. de Beus
Harper & Brothers, 1953
 Buku Teks
Ward, Barbara
The interply of East and West: points of conflct and operation
Norton & Comp , 1957
 Buku Teks
Toynbee, Arnold J.
The world and the west
Oxford University Press, 1957
 Buku Teks
Carpenter, Allan
The encyclopedia of the central west
Facts On File, 1990
 Buku Referensi
Encyclopedia of the American west
editors Charles Phillips, Alan Axelrod
Simon & Schuster Macmillan, 1996
 Buku Referensi