Columbia subject headings:
Harvard subject headings:
Berlin (Germany)--Civilization--20th century.
Berlin (Germany)--History--20th century--Chronology.
Berlin (Germany)--Politics and government--20th century.
Princeton subject headings:
Berlin (Germany)--Civilization--20th century.
Berlin (Germany)--History--20th century--Chronology.
Berlin (Germany)--Politics and government--20th century.