Velasco-Hernández, Mauro, and Mario R. Lucero-Arellano. 2019. “SHORT NOTE - New Locality of the Matzitzi Forniation in the Calapa River, in the Boundary Area Between Oaxaca and Puebla States, Mexico”. Revista Mexicana De Ciencias Geológicas 13 (1):123-27. https://rmcg.geociencias.unam.mx/index.php/rmcg/article/view/1146.