Columbia subject headings:
Harvard subject headings:
Air forces--Germany--History--20th century.
Germany. Heer. Luftstreitkräfte--History.
World War, 1914-1918--Aerial operations, German
Princeton subject headings:
Air forces--Germany--History--20th century.
Germany. Heer. Luftstreitkräfte--History.
World War, 1914-1918--Aerial operations, German.