1. The double points of Mathieu's differential equation;Blanch;Math. Comp.,1969
2. On the effect of the boundary conditions on the eigenvalues of ordinary differential equations;Harrell;Amer. J. Math.,1981
3. Global phase-integral methods;Heading;Quart. J. Mech. Appl. Math.,1977
4. The eigenvalues of Mathieu's equation and their branch points;Hunter;Studies in Appl. Math.,1981
5. The eigenvalues of the angular spheroidal wave equation;Hunter;Studies in Appl. Math.,1982