Samoilenko AM, Samoilenko VG, Sobchuk VS. On periodic solutions of the equation of a nonlinear oscillator with pulse influence. Ukr. Mat. Zhurn. [Internet]. 1999Jun.25 [cited 2024Sep.1];51(6):827–834. Available from: https://umj.imath.kiev.ua/index.php/umj/article/view/4669