1. Resonances in acoustic waveguides;Aslanyan;Quart. J. Mech. Appl. Math.,2000
2. Short-Wavelength Diffraction Theory. Asymptotic Methods;Babich,1991
3. The asymptotic behaviour of the solutions of the wave equation concentrated near the axis of a two dimensional waveguide in an inhomogeneous medium;Buldyrev,1969
4. Integral Functions;Cartwright,1962
5. T. Christiansen, Some upper bounds on the number of resonances for manifolds with infinite cylindrical ends, preprint (2001)