1. Bisplinghoff, R., Ashley, H., and Half man, R., Aeroelasticity, pp. 95, 168; Addison Wesley Publishing Co., Inc., Cambridge, Mass., 1955.
2. Riesz, F., and Sz.Nagy, B., Functional Analysis, p.272; Frederick Ungar Publishing Co., New York, 1955.
3. Burgers, J. M., Advances in Applied Mechanics, "A Mathematical Model Illustrating the Theory of Turbulence," Vol.1, pp.197-199; Academic Press, 1948.