1. I. Faragó, On the nonnegative solution of some system of linear algebraic equations and its application to the numerical solution of partial differential equations,Quad. del Dip. di Matematica, N.12, Bergamo, 1992.
2. I. Faragó, T. Pfeil. Qualitative properties of the heat-conduction equation and of its numerical solution,Alk Mat. Lapok, Budapest, 1993 (to appear, in Hungarian)
3. O. A. Ladyzenskaya, V. A. Solonnikov, N. N. Ural'ceva,Linear and quasilinear equations of parabolic type, Nauka, Moscow, 1967 (in Russian)
4. G. Strang, G. J. Fix,An analysis of the finite element method, Prentice-Hall, Inc. Englewood, 1973.
5. A. N. Tikhonov, A. A. Samarskii,Equations of Mathematical Physics, Nauka, Mascow, 1977 (in Russian).