Distribution and habitats of Bulinus tropicus, snail intermediate host of the conical fluke Calicophoron microbothrium, in South Africa - de Kock, K.; Wolmarans, C.; Bornman, M.; Maree, D. (Suid-Afrikaans Tydskrif vir Natuurwetenskap en Tegnologie / South African Journal of Science and Technology, 2002)