Gómez-Pinilla, I., Larrea, M. T., & Valle, F. J. (1998). Problematic of the Imini pyrolusites in the production of ferromanganese for metallurgical applications. Revista De Metalurgia, 34(Extra), 390–394. https://doi.org/10.3989/revmetalm.1998.v34.iExtra.778