“…We note that the power type nonlinearity f (u) = λ |u| α u or f (u) = λ |u| α+1 with λ ∈ R, α > 0 is of the class C(α), which has been widely studied in classical and biharmonic nonlinear Schrödinger equations. See [3,4,5,6,10,11,14,15,16,20,21,22] for instance.…”