Lucas, Spencer G., William C. McIntosh, and Carlos Manuel González-León. “Eocene Ar40-Ar39 Age Data of Supposed Cretaceous Volcanics (Rhyolite Tuff Formation) in Northeastern Sonora, Mexico”. Revista Mexicana de Ciencias Geológicas 13, no. 2 (January 14, 2019): 184–187. Accessed April 20, 2025. https://rmcg.unam.mx/index.php/rmcg/article/view/1156.