Reuss, Henry S.
The critical decade : an economic policy for America and the free world
McGraw-Hill, 1964
 Buku Teks
Murdock, George Peter
Africa
McGraw-Hill, 1959
 Buku Teks
Murdock, George Peter
Africa
McGraw-Hill, 1959
 Buku Teks
Nielsen, Waldemar A.
Africa
Atheneum, 1966
 Buku Teks
Africa
edited by Phillis M. Martin and Patrick O'Meara
Indiana University Press, 1995
 Buku Teks