1. BAKER, F.C. 1945. The molluscan family Planorbidae. University of Illinois Press, Urbana.
2. BONAVENTURA, C. & BONAVENTURA, J. 1983. Respiratory pigments: Structure and function. In: The Mollusca. (Ed.) Wilbur, K.M., Vol. 2, Ch. 2, Academic Press, London.
3. BONAVENTURA, J. & BONAVENTURA, C. 1981. Preparation of high molecular weight invertebrate hemoglobins. In: Methods in enzymology. Hemoglobins. (Eds) Antonini, E., Rossi-Bernardi, L. & Chiancone, E., Vol. 76(3), Academic Press, London.
4. BROWN, D.S. 1980. Freshwater snails of Africa and their medical importance. Taylor & Francis, London.
5. DEJOURS, P. 1981. Principles of comparative respiratory physiology, 2nd edn, Amsterdam, North Holland.