[1]
Y. R. Petryshyn and A. M. Samoilenko, “Averaging method in multipoint problems of the theory of nonlinear oscillations”, Ukr. Mat. Zhurn., vol. 48, no. 8, pp. 1096–1103, Aug. 1996, Accessed: Dec. 06, 2025. [Online]. Available: https://umj.imath.kiev.ua/index.php/umj/article/view/5253