Ahmed, A.A.M., Ibrahim, N.A. and Idris, M.A. 2006. Laboratory Studies on the Prevalence and Cercarial Rhythms of Trematodes from Bulinus truncatus and Biomphalaria Pfeifferi Snails from Khartoum State,Sudan. Sultan Qaboos University Medical Journal. 6, 2 (Dec. 2006), 65–69.