1. 2Garrick, I. E. and Watkins, C. E. "A Theoretical Study of the Effects of Forward Speed on the Free-Space Sound-Pressure Around Propellers," NACA Rept. 1198,1954.
2. 3Arnoldi, R. A. "Propeller Noise Caused by Blade Thickness," United Aircraft Research Dept., East Hartford, Conn., Rept. R-0896-1,1956.
3. Near field noise of high tip speed propellers in forward flight