1. 2Mechel, F., Mertens, P., and Schilz, W./'Research on Sound Propagation on Sound Absorbent Ducts with Superimposed Airstreams, "Tech. Doc. Rep., AMRL-TDR-62-140.
2. 4Bauer, A. B. "Edgetone Generation," PhD Thesis,Dept. of Aeronautics and Astronautics, Stanford University, Stanford, Calif. 1963.