On pernanence of periodic predator-prey systems with stage structure and impulsive effect. Neliniini Kolyvannya, [S. l.], v. 12, n. 4, p. 527–540, 2009. Disponível em: https://twinhead.imath.kiev.ua/index.php/nosc/article/view/542. Acesso em: 21 jan. 2026.