Columbia subject headings:
Industrial relations--United States--History.
Labor unions--United States--History.
Working class--United States--History.
Harvard subject headings:
Industrial relations--United States--History
Labor unions--United States--History
Labor--United States--History
Working class--United States--History
Princeton subject headings:
Industrial relations--United States--History.
Labor unions--United States--History.
Working class--United States--History.