1. Differentialgleichungen;Kamke,1959
2. The Finite Element Method in Structural and Continuum Mechanics;Zienkiewicz,1967
3. An Analysis of the Finite Element Method;Strang,1973
4. K. Appert, D. Berger, R. Gruber and J. Rappaz, LRP 83/74, EPF-Laussanne, CRPP, submitted to J. Comp. Phys.