1. BABUSKA I and OSBORN J E, Generalized finite element methods their performance and their relation to mixed methods, SIAM J Numer Anal 20 (1983), 510-5367010940528.65046
2. BABUSKA I,OSBORN J and PITKARANTA J, Analysis of mixed methods using mesh dependent norms, Math Comput 35 (1980), 1039-10625834860472.65083
3. BENSOUSSON A, LIONS J L, PAPANICOLAU G, Asymptotic Analysis of Periodic Structures, North-Holland, Amsterdam, 1978 5033300404.35001
4. BREZZI F and RAVIART P A, Mixed finite element methods for 4th order elliptic equations, in Proc of the Royal Irish Academy Conference on Numerical Analysis, Academic Press, London, 1977 6579750434.65085
5. CIARLET P G, The Finite Element Method for Elliptic Equations, North-Holland, Amsterdam, 1978 0383.65058520174