1. Baer, J.G. & Euzet, L. (1961) Classe des Monogènes. In: Traité de
2. Zoologie. Ed. P.P. Grasse. Vol. 4. Paris, Masson. p. 243–325.
3. Bedini, C., Ferrero, E. & Lanfranchi, A. (1973) Fine structure of the eyes in two species of Dalyellidae (Turbellaria: Rhabdocoela). Monitore Zool. Ital. 7: 51 – 70.
4. Bedini, C., Ferrero, E. & Lanfranchi, A. (1977) Fine structural changes induced by circadian light-dark cycles in photoreceptors of Dalyelli-dae (Turbellaria: Rhabdocela). 3. Ultrastruct. Res. 58: 66 – 77.
5. Bedini, C. & Lanfranchi, A. (1974) The fine structure of photoreceptor in two otoplanid species (Turbellaria: Proseriata). Z. Morph. Tiere 77: 175 – 186.