Nonlinear differential equations with solutions bounded on $\mathbb{R}$. Neliniini Kolyvannya, [S. l.], v. 11, n. 1, p. 96–111, 2008. Disponível em: https://twinhead.imath.kiev.ua/index.php/nosc/article/view/465. Acesso em: 21 jan. 2026.