1. Survey lectures on the mathematical foundations of the finite element method;Babuška,1972
2. J. Douglas, Jr., T. Dupont, and L. Wahlbin, Optimal L∞ error estimates for Galerkin approximations to solutions of two point boundary value problems, to appear in Math. of Comp.
3. First Principles of Numerical Analysis;Wendroff,1969
4. An optimal L∞ error estimate for Galerkin approximations to solutions of two point boundary value problems;Wheeler;SIAM J. Numer. Anal.,1973