DVORNYK, A. V.; TKACHENKO, V. I. Almost periodic solutions of systems with delay and nonfixed times of impulsive action. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 68, n. 11, p. 1450–1466, 2016. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/1933. Acesso em: 5 dec. 2025.