“…Finally, we mention that the analysis carried out in this work can be adapted also to different boundary conditions. For instance, one can assume the mixed Neumann-Dirichlet boundary conditions considered in [15] ϕ x (0, t) = ϕ x (L, t) = ψ(0, t) = ψ(L, t) = θ(0, t) = θ(L, t) = ξ(0, t) = ξ(L, t) = 0, or any of the boundary conditions considered in [2]. Clearly, appropriate modifications and precise computations must be done, but no substantial challenges arise.…”