1. Lenhoff, S. G. & Lenhoff, H. M. Hydra and the Birth of Experimental Biology, 1744: Abraham Trembley's Memoirs Concerning the Natural History of a Type of Freshwater Polyp with Arms Shaped like Horns (Boxwood, Pacific Grove, California, 1986).
2. Agata, K. & Watanabe, K. Molecular and cellular aspects of planarian regeneration. Sem. Cell Dev. Biol. 10, 377–383 (1999).
3. Lender, T. in Advances in Morphogenesis Vol. 2 (eds Abercrombie, M. & Brachet, J.) 305–331 (Academic, Inc., New York, 1962).
4. Wolff, E. in Regeneration: 20th Growth Symp. (ed. Rudnick, D.) 53–84 (The Ronald Press Co., New York, 1962).
5. Brøndsted, H. V. Planarian Regeneration 276 (Pergamon, London, 1969).An excellent compendium of experiments carried out on planarians with an extensive bibliography of the classic literature.