International Strategic Minerals Inventory summary report :
niobium (columbium) and tantalum /
by Richard N. Crockett and David M. Sutphin.

APA Citation

Crockett, R. N., Sutphin, D. M., Geological Survey (U.S.). (1993). International Strategic Minerals Inventory summary report: niobium (columbium) and tantalum. [Washington, D.C.?]: U.S. G.P.O. .

MLA Citation

Crockett, R. N, David M Sutphin, and Geological Survey (U.S.). International Strategic Minerals Inventory Summary Report: Niobium (columbium) And Tantalum. [Washington, D.C.?]: U.S. G.P.O. , 1993.

Warning: These citations may not always be complete (especially for serials).