by staff, Branch of Africa and the Middle East, Division of International MineralsU.S. Dept. of the Interior, Bureau of Mines for sale by the Supt. of Docs., U.S. G.P.O.1986
by Charles L. Kimbell, Travis Q. Lyday, and Harold R. NewmanU.S. Dept. of the Interior, Bureau of Mines for sale by the Supt. of Docs., U.S. G.P.O.1985