Brecher, Michael
Oxford University Press, 1959
Buku Teks
Legge, John D., author
Penguin Books, 1973
Buku Teks
Crisp, L. F. (Leslie Finlay), author
Angus & Robertson , 1963
Buku Teks
Economist Books, 1991
Buku Referensi
Karsh, Efraim, author
Free Press, 1994
Buku Referensi