of steepest descent Notes References Bleistein, N. and Handelsman, R. (1975), Asymptotic Expansions of Integrals, Dover, New York. Victor Guillemin and Shlomo Sternberg (1990), Geometric Asymptotics, (see Chapter 1). . Aki, Keiiti; & Richards, Paul G. (2002). "Quantitative Seismology" (2nd ed.), pp 255–256. University Science Books, Wong, R. (2001), Asymptotic Approximations of Integrals, Classics in Applied Mathematics, Vol. 34. Corrected reprint of the 1989 original. Society for Industrial and Applied Mathematics (SIAM), Philadelphia, PA. xviii+543 pages, . Dieudonné, J. (1980), Calcul Infinitésimal, Hermann, Paris External links Mathematical analysis Perturbation theory