Pinzón, J. M. ., R. . Contreras, and C. . Bernardy. “A New Still for the Prevention of Mercury Poisoning in Small-Scale Gold Mining by Amalgam Extraction”. Geofisica Internacional, vol. 42, no. 4, Oct. 2003, pp. 641-4, doi:10.22201/igeof.00167169p.2003.42.4.318.