Pardo, Rosa. “Bifurcation for an Elliptic Problem With Nonlinear Boundary Conditions”. Revista Integración, temas de matemáticas 30, no. 2 (November 28, 2012): 151–226. Accessed July 22, 2024. https://revistas.uis.edu.co/index.php/revistaintegracion/article/view/2903.