1. Michaelsen, W, Dritte Klasse der Vermes Polymera (Annelida): Clitellata Gürtelwürmer, Handbuch der Zoologie. Vermes Polymera: Archiannelida, Polychaeta, Clitellata, Priapulida, Sipunculida, Echiurida, Kükenthal, W. and Krumbach, T., Eds., Berlin: De Gruyter, 1928, vol. 2.
2. De Bauchamp, P., Généralités, Traité de Zoologie, Grassé, P.-P., Ed., Paris: Masson, 1959, vol. 5, pp. 3–11.
3. Purschke, G., Westheide, W., Rodhe, D., and Brinkhurst, R.O., Morphological Reinvestigation and Phylogenetic Relationship of Acanthobdella peledina (Annelida, Clitellata), Zoomorphology, 1993, vol. 113, pp. 91–101.
4. Ferraguti, M, Clitellata. Reproductive Biology of the Invertebrates, Jamieson, B.G.M., Ed., New Delhi: Oxford, 2000, vol. 9, part B, Progress in Male Gamete Biology, pp. 125–182.
5. Sawyer, R.T., Leech Biology and Behaviour, Oxford: Clarendon, 1986.