1. In 'The Republic of the Sudan: A Regional Geography';BARBOUR, K.M.,1961
2. Arch;DAWSON, C.R.; DAGHFOUS, T.; MESSADI, M.; HOSHIWARA, I.; VASTINE, D.W.; YONEDA, c; SCHACHTER, J.,1974
3. MAJCUK, JU. F. (1966) Bull. Wld Hlth Org., 35, 262
4. Arch;NUR, M. 0,1975