Columbia subject headings:
Kommunistische Partei Deutschlands--History.
Labor unions and communism--Germany--History.
Labor unions--Political activity--Germany--History.
Harvard subject headings:
Kommunistische Partei Deutschlands--History.
Labor unions and communism--Germany--History.
Labor unions--Germany--Political activity--History.
Princeton subject headings:
Kommunistische Partei Deutschlands--History.
Labor unions and communism--Germany--History.
Labor unions--Germany--Political activity--History.