Columbia subject headings:
Labor unions--United States.
Working class--United States.
World War, 1914-1918--Economic aspects--United States.
Harvard subject headings:
Labor unions--United States
Labor--United States
Working class--United States
World War, 1914-1918--Economic aspects--United States
Princeton subject headings:
Labor unions--United States.
Labor--United States.
World War, 1914-1918--Economic aspects--United States.