8Davies B. Locating the zeros of an analytic function[ J]. Journal of Comput Phys, 1986, 66:36-49.
9Paul Cristini. Fast and accurate method for the solution of the characteristic equation of shallow water in an isovelocity ocean [ C ] //3rd European Conference on Underwater Acoustic, Herak- lion, Crete, Greece: European Acoustics Association, 1996: 195 - 198.
