1. Survey lectures on the mathematical foundations of the finite element method;Babuška,1972
2. Numerical Methods;Bakhvalov,1977
3. The Finite Element Method for Elliptic Problems;Ciarlet,1978
4. Asymptotic estimates of the L2 n-width;Jerome;J. Math. Anal. Appl.,1968
5. Optimal solution of some two-point boundary value problems;Kacewicz,1989