Columbia subject headings:
Berlin Wall, Berlin, Germany, 1961-1989--Congresses.
Germany (East)--Boundaries--Germany (West)--Congresses.
Germany (East). Grenztruppen der DDR--Congresses.
Germany (West)--Boundaries--Germany (East)--Congresses.
Harvard subject headings:
Border security--Germany (East)--History--Congresses.
Germany (East)--Boundaries--Germany (West)--Congresses.
Germany (East). Grenztruppen der DDR--History--Congresses.
Germany (West)--Boundaries--Germany (East)--Congresses.
Princeton subject headings:
Berlin Wall, Berlin, Germany, 1961-1989--Congresses.
Germany (East)--Boundaries--Germany (West)--Congresses.
Germany (East). Grenztruppen der DDR--Congresses.
Germany (West)--Boundaries--Germany (East)--Congresses.