1. 1) Prandtl, L.: Applications of Modern Hydrodynamics to Aeronautics, NACA TR-116, 1923.
2. 2) Cone, C. D.: The Theory of Induced Lift and Minimum Induced Drag of Nonplanar Lifting Systems, NASA TR-R-139, 1962.
3. 3) Jones, R. T.: The Spanwise Distribution of Lift for Minimum Induced Drag of Wings Having a Given Lift and a Given Bending Moment, NACA TN-2249, 1950.
4. 4) Naik, D. A. and Ostowari, C.: Effects of Nonplanar Outboard Wing Forms on a Wing, J. Aircraft, 27 (1990), pp. 117–122.
5. 5) Andrews, S. A., Perez, R. E., and Allan, W. D. E.: Aerodynamic Implications of Gull’s Drooped Wing-Tips, Bioinspiration Biomimetics, 8 (2013), 046003.