On nonlinear functional system solutions that are continuous for t ∈ R. Neliniini Kolyvannya, [S. l.], v. 19, n. 1, p. 32–47, 2016. Disponível em: https://nosc.imath.kiev.ua/index.php/nosc/article/view/809. Acesso em: 12 apr. 2026.