Columbia subject headings:
Harvard subject headings:
Germany--History--Revolution, 1918--Congresses.
Labor movement--Germany--History--20th century--Congresses.
Labor unions--Germany--History--20th century--Congresses.
Labor unions--Germany--History--Congresses.
Socialism--Germany--History--20th century--Congresses.
Strikes and lockouts--Germany--History--Congresses.
Working class--Political activity--Germany--History--20th century--Congresses.
Princeton subject headings:
Germany--History--Revolution, 1918--Congresses.
Labor unions--Germany--History--Congresses.
Strikes and lockouts--Germany--History--Congresses.