1. Courant, R. & Friedrichs, K. O. 1948 Supersonic Flow and Shock Waves .New York:Interscience.
2. Friedman, M. P. 1960 J. Fluid Mech. 8,193.
3. Chisnell, R. F. 1957 J. Fluid Mech. 2,286.
4. Boyer, D. W. 1960 J. Fluid Mech. 9,401.
5. Wecken, F. 1950 Z. angew. Math. Mech. 30,271.