Park, William W., author
Oxford University Press, 2012
Buku Teks
Hood, Jack B.
West Publishing, 1990
Buku Teks
Gould, William B., IV, author
MIT Press, 1982
Buku Teks
Elkouri, Frank, author
The bureau of nations affairs, 1997
Buku Teks
Player, Macka
West Publishing, 1992
Buku Teks