HULBERT, Richard. Calippus and Protohippus (Mammalia, Perissodactyla, Equidae) from the Miocene (Barstovian-early Hemphillian of the Gulf Coastal Plain. Bulletin of the Florida Museum of Natural History, [S. l.], v. 32, n. 3, p. 221–340, 1988. DOI: 10.58782/flmnh.avxe6832. Disponível em: https://flmnhbulletin.com/index.php/flmnh/article/view/flmnh-vol32-no3. Acesso em: 14 nov. 2025.