Higher Order Convergence Results for the Rayleigh-Ritz Method Applied to Eigenvalue Problems: 2. Improved Error Bounds for Eigenfunctions. R.S. Varga; J.G. Pierce — 1972 Numerische Mathematik
Error Bounds for the Galerkin Method Applied to Singular and Nonsingular Boundary Value Problems. J.G. Pierce; J.W. Dailey — 1972 Numerische Mathematik