Lakusta L. M., PetryshynR. I., and SamoilenkoA. M. “Averaging of Boundary-Value Problems With Parameters for Multifrequency Impulsive Systems”. Ukrains’kyi Matematychnyi Zhurnal 54, no. 9 (September 25, 2002): 1237-1249. Accessed December 14, 2024. https://umj.imath.kiev.ua/index.php/umj/article/view/4162.