BIGUN, Ya. I. Averaging of Oscillation Systems with Delay and Integral Boundary Conditions. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 56, n. 2, p. 257–263, 2004. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/3749. Acesso em: 14 apr. 2025.