Columbia subject headings:
Harvard subject headings:
Archives--Germany (East)--History.
Archives--Germany--History.
Germany (East)--History--Sources.
Germany--History--Sources.
Secret service--Germany (East)--History--Sources.
Secret service--Germany--History--Sources.
Princeton subject headings:
Germany (East)--Politics and government.
Germany (East)--Social conditions.
Internal security--Germany (East)