PETRYSHYN, R. I.; SAMOILENKO, A. M.; Sopronyuk Т. M. Construction of an Integral Manifold of a Multifrequency Oscillation System with Fixed Times of Pulse Action. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 55, n. 5, p. 641–662, 2003. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/3940. Acesso em: 6 dec. 2025.