1. Barlow, H. M. 1947 Micro-waves and wave guides. London: Constable.
2. McLachlan, N.W. 1934 Bessel functions for engineers. Oxford: Clarendon Press.
3. Rayleigh, J. W. Strutt, Baron 1894 The theory of sound. London: Macmillan & Co.
4. Weatherburn, C. E. 1939 Elementary vector analysis. London: G. Bell & Sons Ltd.
5. Whittaker, E.T. & Watson, G. N. 1927 A course of modern analysis. Cambridge University Press.