1. Amen R (1992) Schistosomes modulate the defence system of their intermediate hosts. PhD Thesis. Vrije Universiteit, Amsterdam, 97
2. Croxton FE, Cowden DJ, Klein S (1975) Applied general statistics, 3rd edn. Prentice-Hall of India, New Delhi
3. Davies PS, Partridge T (1972) Limpet haemocytes. 1. Studies on aggregation and spike formation. J Cell Sci 11:757?769
4. Dikkeboom R, van der Knaap WPW, Meuleman EA et al. (1984) Differences between blood cells of juvenile and adult specimens of Lymnaea stagnalis. Cell Tissue Res 238:43?47
5. Dikkeboom R, van der Knaap WPW, Meuleman EA et al. (1985) A comparative study on the internal defense system of juvenile and adult Lymnaea stagnalis. Immunology 55:547?553