Columbia subject headings:
Bremen (Germany)--Economic conditions.
Labor unions--Germany--Bremen--History--20th century.
Working class--Germany--Bremen--History--20th century.
Harvard subject headings:
Bremen (Germany)--Economic conditions.
Labor unions--Germany--Bremen--History--20th century.
Working class--Germany--Bremen--History--20th century.
Princeton subject headings:
Labor movement--Germany--Bremen--History.
Socialism--Germany--History.