Columbia subject headings:
Catholic labor unions--Germany--Bibliography.
Labor unions and communism--Germany--Bibliography.
Labor unions--Germany (West)--Bibliography.
Labor unions--Germany--Bibliography.
Socialism--Germany--Bibliography.
Harvard subject headings:
Catholic labor unions--Germany--Bibliography.
Labor unions and communism--Germany--Bibliography.
Labor unions--Germany (West)--Bibliography.
Labor unions--Germany--Bibliography.
Socialism--Germany--Bibliography.
Princeton subject headings:
Labor movement--Germany--Bibliography.