Tham khảo North_American_O-47

Ghi chú
    Chú thích
    1. 1 2 3 "U.S. Army Aircraft 1908-1946" by James C. Fahey, 1946, 64pp.
    2. 1 2 Swanborough and Bowers 1964
    Tài liệu
    • Eden, Paul and Soph Moeng. The Complete Encyclopedia of World Aircraft. London: Amber Books Ltd., 2002. ISBN 0-7607-3432-1.
    • Fahey, James C. U.S. Army Aircraft 1908-1946. New York: Ships and Aircraft, 1946.
    • Swanborough, F.G. and Peter M. Bowers. United States Military Aircraft Since 1909. New York: Putnam New York, 1964. ISBN 0-85177-816-X.