Verger, P. 1976. Trade Relations between the Bight of Benin and Babia Seventeenth to the Nineteenth Century. Ibadan, Ibadan University Press.  
Washington, J. 1838. Some Account of Mohammedu-Sisëi, a Mandingo, of NyániMarú on the Gambia, Journal of the Royal Geographical Society, No. 8, pp. 448-54.