Gentilli, A., Scali, S. and Sacchi, R. (2006) “Morphometric differences between extant and extinct Italian populations of the adder, <em>Vipera berus</em> (Linnaeus, 1758)”, Acta Herpetologica, 1(1), pp. 65–71. doi: 10.13128/Acta_Herpetol-1251.