1. A. M. Samoilenko, M. O. Perestyuk, and I. O. Parasyuk, Differential Equations [in Ukrainian], Kyivs’kyi Universytet, Kyiv (2010).
2. V. I. Sobolev, Lectures on Additional Chapters of Mathematical Analysis [in Russian], Nauka, Moscow (1968).
3. A. M. Samoilenko and A. D. Myshkis, “Systems with pushes at given times,” Mat. Sb., 74, No. 2, 202–208 (1967).
4. A. M. Samoilenko and N. A. Perestyuk, Impulsive Differential Equations [in Russian], Vyshcha Shkola, Kiev (1987).
5. E. P. Trofimchuk and S. I. Trofimchuk, “Impulse systems with fixed shock times of general disposition: Existence, uniqueness of solution, and the well-posedness of the Cauchy problem,” Ukr. Mat. Zh., 42, No. 2, 230–237 (1990); English translation:Ukr. Math. J., 42, No. 2, 204–209 (1990).