Columbia subject headings:
Forschungsanstalt der Deutschen Reichspost--History.
Hakeburg (Kleinmachnow, Germany)--History.
Kleinmachnow (Germany)--History.
Harvard subject headings:
Forschungsanstalt der Deutschen Reichspost--History.
Hakeburg (Kleinmachnow, German)--History.
Hakeburg (Kleinmachnow, Germany)--History.
Kleinmachnow (Germany)--History.
Princeton subject headings:
Deutsche Reichspost--History.
Hakeburg (Kleinmachnow, Germany)--History.
Kleinmachnow (Germany)--History--20th century.
Military research--Germany--History--20th century.