Chant, Christopher, author
Chancellor Press , 1999
Buku Referensi
Gage, John D., author
Cambridge University Press, 1992
Buku Teks
Nordquist, Myron H., author
Martinus Nijhoff , 2009
Multimedia
Myron H. Nordquist, Tommy T.B. Koh , John Norton Moore
Martinus NijHoff, 2009
Buku Teks
Departhemen of Geography University of Waterloo, 2005
Buku Teks