“…But such technique offers further possible generalizations, first to study the problems, like e.g. Korteweg-de Vries equation and its extensions [7,8,12,13], where the solutions are obtained as a limit of solutions to parabolic regularizations of such equations (the method known as vanishing viscosity technique, originated by Hopf, Oleinik, Lax in 1950th); see also [9,10]. Another possible application of Henry's technique is to study critical problems (e.g.…”