Columbia subject headings:
Harvard subject headings:
Berliner Verkehrs-Betriebe (BVG)--History.
Local transit--Germany--Berlin--History--20th century.
Transportation--Germany--Berlin--History--20th century.
Princeton subject headings:
Berliner Verkehrs-Betriebe (BVG)--History.
Local transit--Germany--Berlin--History--20th century.
Transportation--Germany--Berlin--History--20th century.