Columbia subject headings:
Harvard subject headings:
Berlin (Germany)--History--1945-1990
Berlin Wall, Berlin, Germany, 1961-1989.
Germany (East)--Boundaries--Germany (West)
Germany (West)--Boundaries--Germany (East)
Princeton subject headings:
Berlin Wall, Berlin, Germany, 1961-1989.
Germany (East)--Foreign relations--Germany (West)
Germany (East)--History.
Germany (West)--Foreign relations--Germany (East)
Germany--History--1945-1990.