Não informado. (1925). Information Circular. U.S. Department of the Interior, Bureau of Mines.
Style de citation Chicago (17e éd.)Não informado. Information Circular. Washington: U.S. Department of the Interior, Bureau of Mines, 1925.
Style de citation MLA (8e éd.)Não informado. Information Circular. U.S. Department of the Interior, Bureau of Mines, 1925.
Attention : ces citations peuvent ne pas être correctes à 100%.