KITANOV, P. M.; PLOTNIKOV, V. A. Bogolyubov theorem for quasidifferential equations with pulses. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 49, n. 11, p. 1504–1511, 1997. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/5149. Acesso em: 5 dec. 2025.