Euler approximation of nonconvex discontinuous differential inclusions. Donchev, Tzanko (2002) Analele Ştiinţifice ale Universităţii “Ovidius" Constanţa. Seria: Matematică
Explicit Difference Approximations of the One-Dimensional Diffusion Equation, Using a Smoothing Technique. G.R. JOUBERT (1971) Numerische Mathematik