Columbia subject headings:
Harvard subject headings:
Germany (East)--History--Congresses.
Germany (East)--Relations--Soviet Union--Congresses.
Soviet Union--Relations--Germany (East)--Congresses.
Princeton subject headings:
Germany (East)--History--Congresses.
Germany (East)--Relations--Soviet Union--Congresses.
Soviet Union--Relations--Germany (East)--Congresses.