1. Goldstein, S. 1930 Proc. Camb. Phil. Soc. 26,1.
2. Dorodnitsyn, A. A. 1962 In Advances in Aeronautical Sciences , vol. 3.Pergamon.
3. Korst, H. H. 1956 J. Appl. Mech. 23,593.
4. Ting, L. 1959 J. Math. Phys. 38,153.
5. Chapman, D. R. 1950 N.A.C.A. Rep. no. 1051.