Rujukan Curtiss YP-20

  1. ↑ Fitzsimons, Bernard, ed. Illustrated Encyclopedia of Weapons and Warfare (London: Phoebus, 1978), Volume 12, p.1255.
  2. ↑ Fitzsimons, p.1255.
  3. ↑ Bowers, Peter M. (1979). Curtiss aircraft, 1907-1947. London: Putnam. m/s. 256–266. ISBN 0370100298.
  4. ↑ Lednicer, David. "The Incomplete Guide to Airfoil Usage". m-selig.ae.illinois.edu. Dicapai pada 16 April 2019.

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