Columbia subject headings:
Harvard subject headings:
Germany (East)--Boundaries--Germany (West)
Germany (East)--Relations--Germany (West)
Germany (West)--Boundaries--Germany (East)
Germany (West)--Relations--Germany (East)
Internal security--Germany (East)
Princeton subject headings:
Germany (East)--Boundaries--Germany (West)
Germany (East)--Relations--Germany (West)
Germany (West)--Boundaries--Germany (East)
Germany (West)--Relations--Germany (East)
Internal security--Germany (East)