1. Visser, W. The finite element method in deformation and heat conduction problems, thesis. Delft, 1968.
2. Oliviera, E.R.A. Int. J. Solids Structures 4 (1968) 929.
3. Patterson, C. Sufficient conditions for convergence in the finite element method for any solution of finite energy, Sheffield 1972.
4. Grandall, S.H. Engineering Analysis, London, Mc Graw-Hill Book Cy., 1956.
5. Wilson, E.L. and R.W. Clough Symp. on the use of computers in civil engineering, Lisbon, 1962.