Columbia subject headings:
Harvard subject headings:
Aerial photography--Germany--History.
Bertele, Ludwig J., 1900-1985.
Geometrical optics--Germany--History.
Optical instruments--Germany--Design and construction--History.
Photogrammetrists--Germany--Biography.
Photographic optics--History.
Princeton subject headings:
Bertele, Ludwig J., 1900-1985.
Optical engineers--Germany--Biography.
Photographic optics--History.