Columbia subject headings:
Harvard subject headings:
Labor movement--Germany--History
Labor movement--Germany--History--19th century.
Labor movement--Germany--History--20th century
Social conflict--Germany--History--19th century.
Social conflict--Germany--History--20th century.
Princeton subject headings:
Labor movement--Germany--History--19th century.
Labor movement--Germany--History--20th century.
Social conflict--Germany--History--19th century.
Social conflict--Germany--History--20th century.