Corona-Esquivel, Rodolfo, and Gloria Alencáster. “Rudists from the Peña Colorada Iron Mine and La Minita Sulfide Deposit, States of Colima and Michoacán, SW Mexico”. Revista Mexicana De Ciencias Geológicas, vol. 12, no. 2, Feb. 2019, pp. 185-90, https://www.rmcg.unam.mx/index.php/rmcg/article/view/1190.