The importance of leeches in the life cycle of the order Strigeidida (Trematoda).

Vojtek, J., Opravilová, V., Vojtková, L., (1967). Folia Parasitologica 14(2), 107-119. Praha, not specified language

The ecology of the British freshwater leeches.

Mann, K. H., (1955). Journal of Animal Ecology 24(1), 98-119. English language