Columbia subject headings:
Social classes--Germany--History--19th century.
Social movements--Germany--History--19th century.
Working class--Germany--History--19th century.
Harvard subject headings:
Social classes--Germany--History--19th century.
Social movements--Germany--History--19th century.
Working class--Germany--History--19th century
Princeton subject headings:
Social classes--Germany--History--19th century.
Social movements--Germany--History--19th century.
Working class--Germany--History--19th century.