1 literature reference for Vipera ursinii NILSON & ANDRÉN 2001:

Author: Nilson,G.; ANDRÉN,C. & JOGER,U.
Year: 1993
Title: A re-evaluation of the taxonomic status of the Moldavian steppe viper based on immunological investigations, with a discussion of the hypothesis of secondary intergradation between Vipera ursinii rakosiensis and Vipera (ursinii) renardi.
Source: Amphibia-Reptilia 14: 45-57