Lewis, William Arthur, 1915-
University of Ghana by the Ghana Pub, 1971
Buku Teks
Lockwood, William W.
Princeton Princeton University Press , 1954
Buku Teks
Broadbridge, Seymour
Frank Cass, 1976
Buku Teks
Arndt, Heinz Wolfgang, 1915-2002
F.W. Cheshire , 1968
Buku Teks
Boxer, A. H.
Melbourne University Press, 1966
Buku Teks