Columbia subject headings:
Harvard subject headings:
Aeronautics, Commercial--Germany (East)--History.
Aeronautics--Germany (East)--History.
Aeronautics--Germany (East)--Safety measures.
Airlines--Germany (East)--History.
Airplanes--Piloting--Germany (East)
Interflug (Airline)--History.
Princeton subject headings:
Aeronautics, Commercial--Germany (East)--History.
Aeronautics--Germany (East)--History.
Aeronautics--Germany (East)--Safety measures.
Airlines--Germany (East)--History.
Airplanes--Piloting--Germany (East).