BEREZOVSKY, A. A.; LENYUK, M. P.; SAMOILENKO, A. M. School-Seminar “Nonlinear boundary-value problems in Mathematical Physics and their applications”. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 48, n. 6, p. 863–865, 1996. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/5289. Acesso em: 5 dec. 2025.