Columbia subject headings:
Harvard subject headings:
Border security--Germany (East)
Germany (East)--Boundaries--Germany (West)
Germany (West)--Boundaries--Germany (East)
Political persecution--Germany (East)
Princeton subject headings:
Border security--Germany (East).
Germany (East)--Boundaries--Germany (West)
Germany (West)--Boundaries--Germany (East)
Political persecution--Germany (East)