BLANCO-PIÑÓN, Alberto; GARIBAY-ROMERO, Luis M.; ALVARADO-ORTEGA, Jesús. 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. 24, n. 1, p. 25–30, 2018. Disponível em: https://rmcg.unam.mx/index.php/rmcg/article/view/754. Acesso em: 15 mar. 2025.