1. Arkell, A. J., Early Khartoum (Oxford University Press London, 1949).
2. Arkell, A. J., Shaheinab, 101 (Oxford University Press London, 1953).
3. Williams, M. A. J., Nature, 211, 270–1 (1966).
4. Williams, M. A. J., Nature, 211, 270–1 (1966).
5. Hurst, H. E., and Phillips, P., The Nile Basin, 3 (second suppl.) (Physical Department Paper No. 37, Schindler's Press, Cairo, 1939).