Perrilliat, María del Carmen, et al. “Middle Eocene Cypraeoideans from the San Juan Formation, Chiapas, Southern Mexico”. Revista Mexicana De Ciencias Geológicas, vol. 20, no. 1, June 2018, pp. 41-51, https://www.rmcg.unam.mx/index.php/rmcg/article/view/954.