Pérez-Crespo, Víctor Adrián, et al. “Paleoenvironment of the Central Depression of Chiapas, Based on Stable Carbon and Oxygen Isotopes”. Revista Mexicana De Ciencias Geológicas, vol. 32, no. 2, Jan. 2018, pp. 273-82, doi:10.22201/cgeo.20072902e.2015.2.580.