STINNESBECK, Wolfgang; LÓPEZ-OLIVA, José Guadalupe; FREY, Eberhard; IFRIM, Christina; GIERSCH, Samuel. The oldest stratigraphic record of the Late Cretaceous shark Ptychodus mortoni Agassiz, from Vallecillo, Nuevo León, northeastern Mexico. Revista Mexicana de Ciencias Geológicas, [S. l.], v. 25, n. 2, p. 365–366, 2018. Disponível em: https://rmcg.unam.mx/index.php/rmcg/article/view/665. Acesso em: 15 mar. 2025.