1. Willis, D. R. 1965 J. Fluid Mech. 21,21.
2. Chahine, M. T. & Narasimha, R. 1963 Jet Propulsion Laboratory Rep. no. 32–459.
3. Willis, D. R. 1964 Princeton University Aeronautical Engineering Rep. no. 683.
4. Liepmann, H. W. 1960 J. Fluid Mech. 10,65.
5. Willis, D. R. 1960 Royal Institute of Technology, Kth Aero TN 52.