"Methods of sampling and analyzing coal-mine dusts for incombustible content."; "Greenwald, H. P. (Harold Putnam), 1893-", "Selvig, W. A. (Walter Alfred), 1886-1972.", "Owings, C. W. (Clarence Watson), 1894-"; "Coal dust--Sampling.", "Coal dust--Analysis. "; "Selvig, W. A. (Walter Alfred), 1886-1972.", "Greenwald, H. P. (Harold Putnam), 1893-", "Owings, C. W. (Clarence Watson), 1894-"; "1940"; "

Serial issue. Issued as: United States. Bureau of Mines. Information circular, 7113 (1940:July).

"; ""; "P19471"; "pec"; "Coal dust--Sampling.", "Coal dust--Analysis. "; "14256"; .