Critical cases of π-stability of a nonautonomous essentially nonlinear equation of order $n$. Neliniini Kolyvannya, [S. l.], v. 6, n. 2, p. 171–177, 2003. Disponível em: https://twinhead.imath.kiev.ua/index.php/nosc/article/view/258. Acesso em: 22 jan. 2026.