Lamar, William W., and Mahmood Sasa. 2003. “A New Species of Hognose Pitviper, Genus <i>Porthidium</i≫, from the Southwestern Pacific of Costa Rica (Serpentes: Viperidae)”. Revista De Biología Tropical 51 (3-4):797–804. https://revistas.ucr.ac.cr/index.php/rbt/article/view/16051.