Westview Press, 1989
Buku Teks
Westview Press, 1989
Buku Teks
by the Economist Intelligence Unit and the Cartographic Dept. of the Clarendon Press
Oxford University Press, 1956
Buku Referensi
Gyeszly, Suzanne D., author
The Borgo Press, 1994
Buku Referensi
by Olivier Blanchard ... [et.al.]
MIT Press, 1991
Buku Teks