1. Ivanov, A. V. & Yu. V. Mamkaev, 1973. Resnichnyye chervi (Tur-bellaria), ikh proiskhozhdenie i evolutsiya. Filogeneticheskie ocherki. Nauka, Leningrad, 221 pp. (Turbellaria, their origin and evolution. Phylogenetic essays. In Russian.)
2. Kotikova, E. A., 1979. Osobennosti evolyutsii nervnogo appara-ta tsestod. Tr. Zool. Inst. Akad. Nauk USSR 84: 34–38. (Onpeculiarities of the evolution of the nerve apparatus in Ce-stodes. In Russian, English res.)
3. Kotikova, E. A., 1985. Comparative characterization of the nervous system of the Turbellaria. This volume.
4. Mamkaev, Yu. V., 1966. Morfologicheskoye mnogoobraziye kak pokazatyel primitivnosti gruppy. In E. A. Frolova (ed.), Nauchnaya konferentsiya, posvyashchennaya 100-letiyu so dnya rozhdeniya akademika A. N. Severtsova, Moskva, 22–24 dekabrya 1966 g., Tezisy dokladov. Nauka, Moskva: 18-20. (The morphological diversity as a primitive-group criterion. In Russian.)
5. Mamkaev, Yu. V., 1967. Ocherki po morfologii beskishechnykh turbellarij. Tr. Zool. Inst. Akad. Nauk USSR 44: 26–108. (Essays on the morpholoey,of acoelous turheleunainans. In Rus-sian.)