GONÇALVES, José Valdo, MARCIAL, Marcos R. and MIYAGAKI, Olimpio H. Topological structure of the solution set of singular equations with sign changing terms under Dirichlet boundary condition. Topological Methods in Nonlinear Analysis. Online. 1 March 2015. Vol. 47, no. 1, pp. 73 - 89. [Accessed 14 June 2026]. DOI 10.12775/TMNA.2015.091.