di Yorio, C., García-Carcedo, F., Hernández, A., Ayala, N. and Cornejo, N. (1998) “Beneficiation of Venezuelan graphitic ore through electrostatic separation and direct flotation”, Revista de Metalurgia, 34(Extra), pp. 409–412. doi: 10.3989/revmetalm.1998.v34.iExtra.782.