TY - JOUR AU - V. N. Pavlenko AU - A. A. Asryan TI - Periodic solutions existence for a second order differential equation with a discontinuous nonlinearity JO - Čelâbinskij fiziko-matematičeskij žurnal PY - 2019 SP - 323 EP - 332 VL - 4 IS - 3 PB - mathdoc UR - http://geodesic.mathdoc.fr/item/CHFMJ_2019_4_3_a4/ LA - ru ID - CHFMJ_2019_4_3_a4 ER -