OGUL, B. On the application of the averaging method to one problem of optimal control with unfixed time. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 76, n. 10, p. 1497–1504, 2025. DOI: 10.3842/umzh.v76i10.8606. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/8606. Acesso em: 5 dec. 2025.