Columbia subject headings:
Germany (East)--Congresses.
Harvard subject headings:
Germany (East)--Economic conditions--Congresses.
Germany (East)--History--Congresses.
Germany (East)--History.
Germany (East)--Social conditions--Congresses.
Germany (East)--Social conditions.
Opposition (Political science)--Germany (East)--Congresses.
Princeton subject headings:
Germany (East)--Congresses.