LI, Y.; SHU, X.; XU, Y. Multiple solutions of boundary value problem. Tamkang Journal of Mathematics, [S. l.], v. 37, n. 2, p. 149–154, 2006. DOI: 10.5556/j.tkjm.37.2006.159. Disponível em: https://journals.math.tku.edu.tw/index.php/TKJM/article/view/159. Acesso em: 5 may. 2024.