O'Fahey, R.S. and Spaulding, J.L. 1974. Kingdoms of the Sudan.
@book{ofaheyandspaulding1974, author = {O'Fahey, R.S. and Spaulding, J.L.}, key = {O'Fahey and Spaulding (1974)}, title = {Kingdoms of the Sudan}, year = {1974} }