Não informado. (1925). Information Circular. U.S. Department of the Interior, Bureau of Mines.
Chicagoスタイル(17版)引用形式Não informado. Information Circular. Washington: U.S. Department of the Interior, Bureau of Mines, 1925.
MLA(8版)引用形式Não informado. Information Circular. U.S. Department of the Interior, Bureau of Mines, 1925.
警告: この引用は必ずしも正確ではありません.