Columbia subject headings:
American Federation of Labor--History--Sources.
Labor unions--United States.
Mitchell, John, 1870-1919--Sources.
United Mine Workers of America--History--Sources.
Harvard subject headings:
American Federation of Labor--History--Sources.
Labor unions--United States--History--Sources.
Mitchell, John, 1870-1919.
United Mine Workers of America--History--Sources.
Princeton subject headings: