1. Some general texts on the asymptotic expansion of integrals: Bleistein, N., and Handelsman, R. A., Asymptotic Expansions of Integrals, Holt, Rinehart and Winston, New York, 1975.
2. Copson, E. T., Asymptotic Expansions, Cambridge University Press, Cambridge, 1967.
3. Olver, F. W. J., Asymptotics and Special Functions, Academic Press, Inc., New York, 1974.
4. See also Refs. 15 to 17. Integral representations of special functions are given in Refs. 10 to 12 and: Gradshteyn, I. S., and Ryzhik, I. W., Tables of Integrals, Series, and Products, 4th ed., Academic Press, Inc., New York, 1965.