1. The NASA high-speed turboprop program;Dugan;NASA TM-81561,1980
2. A report prepared by NASA (OAST) at the request of the Committee on Science and Technology, 1981. U.S. House of Representatives. An accelerated and enhanced advanced turboprop program.
3. Strategies for aircraft interior noise reduction in existing and future propeller aircraft;Metzger;SAE Paper No. 810560,1981
4. Propeller noise signatures and their use;Johnston;Journal of Aircraft,1981
5. The active control of sound propagation in long ducts;Swinbanks;Journal of Sound and Vibration,1973