“…whereα ijk are non-negative coefficients, ω j ∈ Ω,α ik are non-negative continuous functions on Ω. There exists a wide literature on these kind of BCs, we refer the reader to the reviews [4,10,29,33,39,42] and the papers [24,25,34,35,41]. We point that that this setting can also be applied to nonlinear, nonlocal BCs, which have seen recently attention in the framework of (local) elliptic equations, we refer the reader to the papers by Cianciaruso and co-authors [8] and Goodrich [18,19,20,21].…”