Ahmed, Abdel Aziz M, Nidal A Ibrahim, and Mohamed A Idris. 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):65-69. https://journals.squ.edu.om/index.php/squmj/article/view/1266.