Columbia subject headings:
Harvard subject headings:
Aeronautics--Germany--History
Aerospace engineering--Germany--History.
Airplanes--Germany--Fuel--History.
Hydraulic fluids--History.
Logistics--History.
Princeton subject headings:
Aeronautics--Germany--History.
Aerospace engineering--Germany--History.
Airplanes--Germany--Fuel--History.
Hydraulic fluids--History.
Logistics--History.