Coal-mine gases
Coal-mine gases. (U.S. Federal board for vocational education. Bul. 39) 35p pa ’20
Coal mines
Award and recommendations of the United States bituminous coal commission accepted by the President, 1920. U.S. Bituminous coal comm. 120p pa ’20
Comfort stations
Wisconsin public comfort station code and rest room suggestions. (Wisconsin. State board of health) 62p pa ’20 Madison, Wis.
Commerce
Trade of the United States with the world, 1918–1919. Part 1—Imports. (U.S. Bur. of foreign and domestic commerce. Miscellaneous ser. 106) 103p pa ’20
Commercial organizations
Commercial and industrial organizations of the United States; rev. to Nov. 1, 1919. (U.S. Foreign and domestic commerce bureau. Miscellaneous ser. 99) 121p pa ’20