“…here, in (1.3), αijk , βijkl are non-negative coefficients and ω i , τ i ∈ O while, in (1.4), αjk , βjkl are non-negative continuous functions on O. In particular we observe that nonlinear, nonlocal BCs have seen recently attention in the framework of elliptic equations: we refer the reader to the papers [5,6,14,15,17,18,24] and references therein. We wish to point out that an advantage of our setting, with respect to the theory developed in [5,6,14,15,17,24], is the possibility to allow also gradient dependence within the functionals occurring in the BCs.…”