Cluj-Napoca

COMMODITIES RESEARCH UNIT LIMITED, THE BASE METALINDUSTRIES OF EASTERN EUROPE, NOV. 1990.ATLAS OF EASTERN EUROPE, CENTRAL INTELLIGENCE AGENCY,AUG. 1990.BOMSEL AND VON HIRSCHHAUSEN, THE MINING ANDMETALLURGICAL INDUSTRIES OF EASTERN EUROPE, CERNA, VOL.1,JULY 1991.METALLURGICAL INDUSTRIES OF EASTERN EUROPE, CERNA, VOL.3,JULY 1991, PP.217-233.HANNOVER, BUNDESANSTALT FUR GEOWISSENSCHAFTEN UNDROHSTOFFE, RUMANIEN, DEC. 1977.ATLAS OF THE WORLD, THE TIMES BOOK COMPANY, SLATE #82,1983.HURLBUT, CORNELIUS S., DANA'S MANUAL OF MINERALOGY,EIGHTEENTH EDITION, 1971.MINERAL FACTS AND PROBLEMS, UNITED STATES DEPARTMENT OFTHE INTERIOR, BUREAU OF MINES BULLETIN 675, EDITION 1985.