CHUIKO, S. M. Weakly nonlinear boundary-value problem in a special critical case. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 61, n. 4, p. 548–562, 2009. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/3039. Acesso em: 7 dec. 2025.