Columbia subject headings:
Harvard subject headings:
Aircraft industry--Germany--History.
Airplanes--Germany--History.
Airships--Germany--History.
Graf Zeppelin (Airship)--History.
Luftschiffbau Zeppelin--History--20th century.
Zeppelin GmbH--History--20th century.
Zeppelin-Stiftung (Friedrichshafen, Germany)--History--20th century.
Princeton subject headings:
Aircraft industry--Germany--History.
Airplanes--Germany--History.
Airships--Germany--History.
Graf Zeppelin (Airship)--History.
Luftschiffbau Zeppelin--History--20th century.