| Reference | {Deposit:: NIEBERLEIN AND OTHERS, 1954, PROGRESS REPORT ON THE DEVELOPMENT OF COLUMBIUM IN ARKANSAS FOR 1953, U. S. BUREAU OF MINES REPT. INV. 5064}{Deposit:: GORDON AND OTHERS, 1958, GEOLOGY OF THE ARKANSAS BAUXITE REGION, U. S. G. S. PROF. PAPER 299} |