Não informado. (1976). Minerals & Materials. U.S. Department of the Interior, Bureau of Mines.
Chicagoスタイル(17版)引用形式Não informado. Minerals & Materials. Washington: U.S. Department of the Interior, Bureau of Mines, 1976.
MLA(8版)引用形式Não informado. Minerals & Materials. U.S. Department of the Interior, Bureau of Mines, 1976.
警告: この引用は必ずしも正確ではありません.