References
SMITH, A., 1979, THE MINING OF TUNGSTEN, IN MINING JOURNAL BOOKS, LTD., TUNGSTEN: PROCEEDINGS OF THE FIRST INTERNATIONAL TUNGSTEN SYMPOSIUM, STOCKHOLM, P. 34, 56..BUNDESANSTALT FUR GEOWISSENSCHAFTEN UND ROHSTOFFE, HANNOVER, 1977, UNTERSUCHUNGEN UBER MINERALISCHER ROHSTOFFE: IX WOLFRAM, P. 9..UNITED STATES BUREAU OF MINES, 1951, MINERAL TRADE NOTES, NO. 5, P. 32-34..STAFF, 1979, TUNGSTEN/MINAS DA BORRALHA, MINING JOURNAL, VOL. 292, NO. 7491, MARCH 16, 1979, P. 202..CONDE, L. N., PEREIRA, V., RIBEIRO, A., AND THADEU, D., 1971, JAZIGOS HIPOGENICOS DE ESTANHO E VOLFRAMIO; LIVRO-GUIA EXCURSAO NO. 7, I CHLAGE, MADRID-LISBOA, LISBOA, P. 47-54..REYNAUD, R., 1982, PRODUCTION AND MARKETING OF PORTUGUESE TUNGSTEN ORES IN PORTUGAL - EUROPEAN COMMUNITIES, EUROPEAN TUNGSTEN SEMINAR, LISBON, MARCH 22-24, 1982, 24 P..GOINHAS, J. AND VIEGAS, L., 1980, PROVINCIA METALOGENETICA ESTANIFERA E TUNGSTENICA, IBERICA, ESTUDOS, NOTAS E TRABALHOS DE SERVICO DO FOMENTO MINEIRO, VOL. XXV, NOS. 3-4, 178 P..ANSTETT, T. F., BLEIWAS, D. I., AND HURDELBRINK, R. J., 1985, TUNGSTEN AVAILABILITY - MARKET ECONOMY COUNTRIES, U. S. BUREAU OF MINES, INFORMATION CIRCULAR 9025, 51 P..CHARTER CONSOLIDATED P.L.C., ANNUAL REPORTS.INTERNATIONAL STRATEGIC MINERALS INVENTORY RECORD W081