The use of questionnaires and parasitological analyses to identify groups at low risk of becoming infected with bilharziasis and the factors that might contribute to this in a community in the endemic area in South Africa - Wolmarans, C.; de Kock, K.; le Roux, J. (Suid-Afrikaans Tydskrif vir Natuurwetenskap en Tegnologie / South African Journal of Science and Technology, 2004)