... Wang and T.-S Yeh, “Exact multiplicity of solutions and S-shaped bifurcation curves for the p-Laplacian perturbed Gelfand problem in one space variable,” Journal of Mathematical Analysis and Applications, ... theory,” Journal of Mathematical Analysis and Applications, vol 69, no 1, pp 131–145, 1979 14 S H Wang, “On S-shaped bifurcation curves,” Nonlinear Analysis: Theory, Methods & Applications, vol ... show that for β large enough, 1.10 has a double S-shaped bifurcation curve with exactly positive solutions for a certain range of λ see Figure Existence and Multiplicity Results when Ω is an Annulus...