Makambal

KASTNER, B. H., ET AL. "NICKEL, UTERSUCHUNGEN UBER ANGEBOTUND NACHFRAGE MINERALISHER ROHSTOFFE." DEUTSCHESINSTITUT FUR WIRTSCHAFTS FORSHUNG. BERLIN. 1978. PP.60-63.MIRANDA, F.E., ET AL. "DATA ON PHILLIPINE MINERAL RESOURCES." INFORMATION CIRCULAR NO. 22. BUREAU OF MINES. MANILA.1978. PP. 12,27."NICKEL." MINERAL ECONOMICS AND INFORMATION DIVISION,BUREAU OF MINES. INFORMATION SERIES NO. 5. MANILA.1978. PP. 1-4.PRIVATE COMMUNICATION. INTERVIEW WITH PHILIPPINE BUREAU OFMINES PERSONNEL. MANILA. NOVEMBER 1980.PRIVATE COMMUNICATION. INTERVIEW WITH DR. RUDI OBIAL, MININGCONSULTANT. MANILA. NOVEMBER 1980.