On stability of solutions of nonstationary differential systems with impulsive effect in a critical case. Neliniini Kolyvannya, [S. l.], v. 14, n. 4, p. 445–467, 2011. Disponível em: https://twinhead.imath.kiev.ua/index.php/nosc/article/view/620. Acesso em: 21 jan. 2026.