“…In this direction we mention the works of de Figueiredo-Girardi-Matzeu [6], Girardi-Matzeu [12] (semilinear problems) and Bai [2], Faraci-Motreanu-Puglisi [4], Faria-Miyagaki-Motreanu-Tanaka [5], García Melián-Sabina de Lis-Takáč [7], Huy-Quan-Khanh [14], Ruiz [26], Tanaka [27] (nonlinear problems) together with Motreanu-Vetro-Vetro [16,17] (nonlinear system problems). For Neumann and Robin problems, there are the recent works of Gasinski-Papageorgiou [10], Papageorgiou-Radulescu-Repovs [24] (semilinear Neumann problems with a differential operator of the form div(a(u)Du), u ∈ W 1,p (Ω)) and Bai-Gasinski-Papageorgiou [3], Papageorgiou-Radulescu-Repovs [25] (nonlinear Robin problems). In these papers the hypotheses on the reaction are different and in many respects more restrictive.…”