Donnelly, Thomas C.
The University of Mexico Press, 1953
Buku Teks
Rosenau, Milton D., Jr, author
Lifetime Learning, 1982
Buku Teks
Vasil, Ray
Victoria University Press, 1988
Buku Teks
Belich, James, author
Penguin Books, 1988
Buku Teks
Barber, Laurie
Century Hutchinson, 1989
Buku Teks