[1] International Scientific Committee for the drafting of a General History of Africa and J. Devisse and J. Vansina, "Africa from the seventh to the eleventh century: five formative centuries ," 1988.

International Scientific Committee for the drafting of a General History of Africa and Devisse, Jean and Vansina, Jan, "Africa from the seventh to the eleventh century: five formative centuries ," 1988.

International Scientific Committee for the drafting of a General History of Africa, Devisse, J., Vansina, J., (1988). "Africa from the seventh to the eleventh century: five formative centuries,"

International Scientific Committee for the drafting of a General History of Africa, Devisse, Jean, Vansina, Jan. (1988). "Africa from the seventh to the eleventh century: five formative centuries,"