Roldán-Contreras, Edmundo, et al. “Use of the System S2o3 (2-) -O2 for the Leaching of Precious Metals Contained in a Mineral From Molango in the State of Hidalgo, Mexico”. European Scientific Journal, ESJ, vol. 14, no. 3, Jan. 2018, p. 48, doi:10.19044/esj.2018.v14n3p48.