Legum, Colin, author
Frederick A. Praeger, 1964
Buku Teks
Griffiths, Ieuan Ll., author
Routledge, 1994
Buku Teks
edited by M. Fortes and E.E. Evans-Pritchard
Oxford University Press, 1950
Buku Teks
The American Society of African Culture, 1966
Buku Teks
UNESCO, 1979
Buku Teks