1. 1) White, R. P. Jr.: The Status of Rotor Noise Technology: One Man’s Opinion, NASA Center for AeroSpace Information (CASI), 1978.
2. 2) Chou, S.-T.: A Study of Rotor Broadband Noise Mechanism and Helicopter Tail Rotor Noise, NASA-CR-177565, 1990.
3. 3) Martin, R. M.: Acoustic Test of a Model Rotor and Tail Rotor: Results for the Isolated Rotor and Combined Configuration, NASA-TM-101550, 1989.
4. 4) Balch, D. T. and Lombardi, J.: Experimental Study of Main Rotor Tip Geometry and Tail Rotor Interaction in Hover. Volume 1. Text and Figures, NASA-CR-177336-VOL-1, 1985.
5. 5) Balch, D. T. and Lombardi, J.: Experimental Study of Main Rotor Tip Geometry and Tail Rotor Interaction in Hover. Volume 2. Run Log and Tabulated Data, NASA-CR-177336-VOL-2, 1985.