Columbia subject headings:
Harvard subject headings:
Anti-Nazi movement--Germany--Ruhr (Region)
Ruhr (Germany : Region)--Politics and government.
Working class--Germany--Ruhr (Region)--Political activity.
Princeton subject headings:
Anti-Nazi movement--History.
Münster in Westfalen (Germany)--Politics and government.
Ruhr (Germany : Region)--Politics and government.
Working class--Germany--Ruhr Valley--Political activity--History.