• [Wiki] http://en.wikipedia.org/wiki/Punctum_pygmaeum.
• [Baur1989] Baur, B. (1989). Growth and reproduction of the minute land snail Punctum pygmaeum (Draparnaud). J. Moll. Stud., 55:383--387. doi:10.1093/mollus/55.3.383 .
• [Kooy2010] Kooijman, S. (2010). Dynamic Energy Budget theory for metabolic organisation. Cambridge Univ. Press, Cambridge.
• [Will1976] Williampson, P. (1976). Size-weight relationships and field growth rates of the landsnail Cepaea nemoralis L. Journal of Animal Ecology, 45(3):875--885.