Columbia subject headings:
Harvard subject headings:
Germany--Foreign relations--Poland--Congresses.
Germany--History--Congresses.
Germany--Relations--Poland--Congresses.
Poland--Foreign relations--Germany--Congresses.
Poland--History--Congresses.
Poland--Relations--Germany--Congresses
Princeton subject headings:
Germany--Foreign relations--Poland--Congresses.
Poland--Foreign relations--Germany--Congresses.