ZAVIZION, G. V. Asymptotic integration of systems of integro-differential equations with degeneracies. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 51, n. 2, p. 170–180, 1999. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/4596. Acesso em: 5 dec. 2025.