Carrasco-Velázquez, Baldomero E., et al. “Geochemistry of Rocks Associated With the Cretaceous Paleokarst in the Actopan Platform: Paleohydrologic Evolution”. Revista Mexicana De Ciencias Geológicas, vol. 21, no. 3, May 2018, pp. 382-96, https://rmcg.geociencias.unam.mx/index.php/rmcg/article/view/883.