Columbia subject headings:
Berlin (Germany)--History--1945-1990.
Berlin (Germany)--History--Blockade, 1948-1949.
Berlin Wall, Berlin, Germany, 1961-1989.
Transportation--Germany--Berlin.
Harvard subject headings:
Berlin (Germany)--History--1945-1990
Berlin (Germany)--History--Blockade, 1948-1949
Berlin Wall, Berlin, Germany, 1961-1989
Transportation--Germany--Berlin.
Princeton subject headings:
Quadripartite Agreement on Berlin
Transit, International--Germany--Berlin.
Transportation--Law and legislation--Germany--Berlin.