TY  - JOUR
AU  - M. A. Krasnosel'skii
TI  - Periodical solutions in the neighbourhood of a singular point of a dynamical system
JO  - Doklady Akademii Nauk
PY  - 1957
SP  - 180
EP  - 183
VL  - 117
IS  - 2
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/DAN_1957_117_2_a4/
LA  - ru
ID  - DAN_1957_117_2_a4
ER  -