1. Al-Yousuf, S. A. H. (1992) Neuropeptides and immunocytochemistry in annelids. Int. Rev. Cytol. 133, 231–308.
2. Csoknya, M., Lengvári, I., Hiripi, L., Elekes, K.,Vincze, J., Szelier, M., Hámori, J. (1993) Serotonin content during the regeneration of nervous system in earthworm (Lumbricus terresris L., Oligohaeta). Acta Biol. Szeged 39, 39–49.
3. Csoknya, M., Lengvári, I., Hiripi, L., Eckert, M., Rapus, J., Elekes, K. (1996) Octopamine in the central nervous system of Oligochaeta: an immunocytochemical and biochemical study. Cell Tissue Res. 285, 27–37.
4. Csoknya, M., Barna, J., Bánvölgyi, T., Hiripi, L., Eckert, M., Hámori, J., Elekes, K. (1997) Octopamine-containing neurons in the alimentary tract of the earthworm. Brain Res. 778, 414–417.
5. Eckert, R., Randall, D., Augustine, G. (1988) Animal physiology, mechanism and adaptations. Freeman, New York.