Chant, Christopher
Chancellor Press , 1999
Buku Referensi
Gage, John D.
Cambridge University Press, 1992
Buku Teks
Myron H. Nordquist, Tommy T.B. Koh , John Norton Moore
Martinus NijHoff, 2009
Buku Teks
Departhemen of Geography University of Waterloo, 2005
Buku Teks
Bowett, D.W. (Derek William)
Manchester University Press, 1967
Buku Teks