Wolfram-Bergbau

1978 ENGINEERING AND MINING JOURNAL INTERNATIONAL DIRECTORYOF MINING AND MINERAL PROCESSING OPERATIONS, MCGRAW-HILL1978, P. 270.WORLD MINING, WHAT'S GOING ON IN WORLD MINING, V. 30, NO. 6,AUGUST 1977, P. 97.ROMAN, GEORGE H., 1979-1980 WORLD MINES REGISTER, MILLERFREEMAN PUBLICATIONS, INC. V. 32, 1979, P. 36, 103.NIGHTINGALE, WILLIAM G., MINING INTERNATIONAL YEARBOOK,1978, THE FINANCIAL TIMES LIMITED, 1978, P. 382, 577.WOLFRAM BERGBAU UND HUTTENGESELLSCHAFT M.B.H. COMPANY REPORT2ND EDITION, JANUARY 1978.MINING MAGAZINE, MINING ACTIVITY IN THE WESTERN WORLD,V. 140, NO. 1, JANUARY 1979, P. 71.TUNGSTEN NEWS, AMAX JULY 1977, P. 1.GIBBS, E.C., ENGINEERING AND MINING JOURNAL, TUNGSTEN-RISINGDEMAND, NEW PRODUCTION FOR 1977, V. 178, NO. 3, MARCH 1977P. 110.MINING JOURNAL, MINING WEEK, V. 291, NO. 7479, DECEMBER 22,1978, P. 483, 484.