Armienta, M.A., Varley, N. y Ramos, E. 2002. Radon and hydrogeochemical monitoring at Popocatépetl volcano, Mexico. Geofísica Internacional. 41, 3 (jul. 2002), 271–276. DOI:https://doi.org/10.22201/igeof.00167169p.2002.41.3.342.