1. Vermooten, V.: Occurrence of renal calculi and their possible relation to diet as illustrated in South African Negroes.JAMA, 109, 857 (1937).
2. Esho, J. O.: Experience with urinary tract calculus disease in Nigerians as seen at the Lagos University Teaching Hospital.Nig. Med. J., 6, 18 (1976).
3. Burkitt, D.: Surgical pathology in the course of the Nile.Ann R. Coll. Surg. Engl., 39, 236 (1966).
4. Blacklock, N. J.: Epidemiology of urolithiasis. In: Williams, D. I., Chisholm, G. D. (eds): Scientific Foundation of Urology, Vol. 1. Heinemann, London 1976, p. 238.
5. Quinland, W. S.: Urinary lithiasis: review of 33 cases in Negroes.Ibid.,53, 791 (1945).