TY  - JOUR
AU  - L. A. Beklaryan
TI  - A new approach to the question of existence of periodic solutions

JO  - Izvestiya. Mathematics 
PY  - 2018
SP  - 1077
EP  - 1107
VL  - 82
IS  - 6
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/IM2_2018_82_6_a0/
LA  - en
ID  - IM2_2018_82_6_a0
ER  -