Yeager, Rodger, author
Westview Press, 1989
Buku Teks
Baldwin, Kenneth David Sutherland, 1920-, author
Basil Blackwell, 1957
Buku Teks
Lubeck, Steven G.
Aldine Publishing Company, 1971
Buku Teks
Macintyre, Stuart, author
Australian Goverment, 1947
Buku Teks
Estell, Kenneth
Visible Ink Press, 1994
Buku Teks