Solomaykin Evgeny I. RussiaНижний НовгородLobachevsky State University of Nizhni Novgorod, 23 Gagarin Avenue, Nizhni Novgorod 603950, Russiae7v4gen5iy@yandex.ru Author's articles Age differences in the leukocyte blood composition of the common viper Vipera berus (Reptilia: Serpentes: Viperidae)