Sancho, J. P., B. Fernández, J. Ayala, M. P. García, and A. Lavandeira. “Uses of the Potassium Permanganate to Eliminate Copper Cyanide from Waste Water Resulting from a Lixiviation Plant in a Gold Mine (II): Pilot Plant Experiences”. Revista De Metalurgia, vol. 47, no. 3, June 2011, pp. 224-33, doi:10.3989/revmetalm.1029.