KARAKOSTAS, George L.; TSAMATOS, Panagiotis Ch. Existence of multiple positive solutions for a nonlocal boundary value problem. Topological Methods in Nonlinear Analysis, [S. l.], v. 19, n. 1, p. 109–121, 2002. Disponível em: https://apcz.umk.pl/TMNA/article/view/TMNA.2002.007. Acesso em: 16 dec. 2025.