XU, L.; CHEN, H. Existence of positive ground solutions for biharmonic equations via Pohožaev-Nehari manifold. Topological Methods in Nonlinear Analysis, [S. l.], v. 52, n. 2, p. 541–560, 2018. Disponível em: https://apcz.umk.pl/TMNA/article/view/TMNA.2018.015. Acesso em: 6 may. 2024.