1. Halfman, R. L., Johnson, H. C., and Haley, S. M. "Evaluation of High-Angle-of-Attack Aerodynamic-Derivative Data and Stall-Flutter Prediction Techniques," TN 2533, Nov.1951, NACA.
2. Fung, Y. C., An Introduction to the Theory of Aeroelasticity, Wiley, New York, 1955, pp.452-453.