Columbia subject headings:
Labor movement--Illinois--Chicago--History--19th century.
Working class--Illinois--Chicago--History--19th century.
Harvard subject headings:
Labor movement--Illinois--Chicago--History--19th century.
Working class--Illinois--Chicago--History--19th century.
Princeton subject headings:
Labor movement--Illinois--Chicago--History--19th century.
Working class--Illinois--Chicago--History--19th century.