Castillo, R. C., S. Ramos, J. Nieto-Obregon, y E. Gonzalez-Partida. 1988. «Carbon Isotopic Analysis in Mexico: A Progress Report on Some Mexican Ore Deposits and Metamorphic Rocks». Geofísica Internacional 27 (1):149-57. https://doi.org/10.22201/igeof.00167169p.1988.27.1.1121.