KitanovP. M. and PlotnikovV. A. (1997) “Bogolyubov theorem for quasidifferential equations with pulses”, Ukrains’kyi Matematychnyi Zhurnal, 49(11), pp. 1504–1511. Available at: https://umj.imath.kiev.ua/index.php/umj/article/view/5149 (Accessed: 27July2024).