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