Elliot, Charles
Praeger, 1975
Buku Teks
Penguin Books, 1978
Buku Teks
Haq, Mahbub ul, 1934-1998, author
Columbia University Press, 1976
Buku Teks
Aboyade, Ojetunji, author
Addison-Wesley, 1983
Buku Teks
Hunter, Guy
Oxford University Press, 1969
Buku Teks