1. P. Shapiro, Massachusetts Institute of Technology, Acoustics and Vibration Laboratory Report No. 83458-83560-1 (1977).
2. E. Pfizenmaier, Deutsche fur Versuchsanstalt Luft- und Raumfahrt Berlin Report No. DLR-FB73-69 (1975).
3. P. Mungur, presented at the Fourth American Institute of Aeronautics and Astronautics Aero-Acoustic Conference, Atlanta, Georgia (1977) Paper 77-1369.
4. J. E. Yates presented at the Fourth American Institute of Aeronautics and Astronautics Aero-Acoustic Conference, Atlanta, Georgia (1977); Paper 77-1352.