1. Peter Beckman,Orthogonal Polynomials for Engineers and Physicists, Boulder, CO, The Golem Press, 1973.
2. Orin J. Farrel, and Bertram Ross,Solved Problem: Gamma and Beta Functions, Legendre Polynomials, Bessel Functions, New York: Macmillan, 1963.
3. Issac M. Horowitz,Synthesis of Feedback Systems, New York: Academic Press, 1963.
4. Richard A. Haddad, and Thomas W. Parsons,Digital Signal Processing: Theory, Applications, and Hardware, New York: Computer Science Press, 1991.
5. R.M. MacRobert,Sperhical Harmonics, New York: Dover, 1948.