1. Atkins, D., 1934. Two parasites of the common cockle Cardium edule; a rhabdocoel Paravortex cardii Hallez and a copepod Paranthessius rostratus (Canu). J. Mar. Biol. Assoc. U.K. 19: 669?676.
2. Ball, S. J., 1916. Development of Paravortex gemellipara. J. Morphol. 27: 453?557.
3. Freeman, R. F. H., 1957. Paravortex scrobiculariae (Graff) in Great Britain. Nature. 180: 1213?1214.
4. Hallez, P., 1909. Biologie, organisation, histologie et embryologie d'un rhabdocoele parasite du Cardium edule L., Paravortex cardii n.sp. Arch. Zool. Exp. Gén. Sér. 4, 9: 429?544.
5. Jennings, J. B. & LeFlore, W. B., 1979. Occurrence and possible adaptive significance of some histochemically demonstrable dehydrogenases in two entosymbiotic rhabdocoels (Platylhelminthes: Turbellaria). Comp. Biochem. Physiol. 62B: 301?304.