1 literature reference for Vipera atra ZUFFI 2002:

Author: Zuffi, Marco A.L.
Year: 2002
Title: A critique of the systematic position of the asp viper subspecies Vipera aspis aspis (Linnaeus, 1758), Vipera aspis atra Meisner, 1820, Vipera aspis francisciredi Laurenti, 1768, Vipera aspis hugyi Schinz, 1833...
Source: Amphibia-Reptilia 23 (2): 191-213