1. Lessen, M. 1950 On stability of free laminar boundary layer between parallel streams,Nat. Adv. Comm. Aero., Wash., no. 979.
2. Watson, G. N. 1944 Theory of Bessel Functions .Cambridge University Press.
3. Carrier, G. 1954 Interface stability of the Helmholtz type,Los Alamos Internal Report.
4. Lin, C. C. 1955 Theory of Hydrodynamic Stability .Cambridge University Press.
5. Rayleigh, Lord 1945 Theory of Sound .New York:Dover.