Reference

Jan W. Amtzen, Tania Trujillo, Roland Butot, Klaas Vrieling, Onno Schaap, Jorge Gutierrez-Rodriguez, Inigo Martinez-Solano (2016): Concordant morphological and molecular clines in a contact zone of the Common and Spined toad (Bufo bufo and B. spinosus) in the northwest of France – Frontiers in Zoology – 2016: 52-0001-52-0012.