“…There is an extensive literature on the numerical solution of convection-diffusion problems. Let us mention, e.g., the papers [1], [2], [22], [23], [27], [29], [32], [34], [35], the monographs [26], [28] and the references therein, devoted mainly to linear problems. The main difficulty which must be overcome is the accurate resolution of the so-called boundary layers.…”