1. Piecewise bicubic interpolation and approximation in polygons;Birkhoff,1969
2. Piecewise Hermite interpolation in one and two variables with applications to partial differential equations;Birkhoff;Numer. Mat.,1968
3. Higher order Rayleigh-Ritz approximations;Fix;J. Math. Mech.,1969
4. Bounds and Approximations for Eigenvalues of Self-adjoint Boundary Value Problems;Fix,1968
5. Developments at an analytic corner of solutions of elliptic partial differential equations;Lehman;J. Maths. Mech.,1959