Columbia subject headings:
Harvard subject headings:
Aeronautical engineers--Germany--Biography
Air pilots--Germany--Biography
Automobile engineers--Germany--Biography.
Engineers--Germany--Biography.
Grade, Hans, 1879-1946.
Princeton subject headings:
Aeronautical engineers--Germany--Biography.
Air pilots--Germany--Biography.
Automobile engineers--Germany--Biography.
Grade, Hans, 1879-1946.