Rodríguez, Ramiro, Rodolfo Olmos, and Julio Payes. 2014. “Measurement of Radon (222Rn) in Thermal Water of Cerro Pacho, Coatepeque Caldera, El Salvador”. Revista geológica De América Central 50 (June):71-82. https://doi.org/10.15517/rgac.v0i50.15108.