Columbia subject headings:
Harvard subject headings:
Berlin (Germany)--Politics and government--1945-1990
Berlin Wall, Berlin, Germany, 1961-1989
Germany (East)--Politics and government--1989-1990
Princeton subject headings:
Berlin (Germany)--Politics and government--1945-1990.
Berlin Wall, Berlin, Germany, 1961-1989.
Germany (East)--Politics and government--1989-1990.