TY  - JOUR
AU  - Yu. S. Bogdanov
TI  - Some tests for the absence of closed trajectories
JO  - Doklady Akademii Nauk
PY  - 1958
SP  - 939
EP  - 940
VL  - 120
IS  - 5
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/DAN_1958_120_5_a1/
LA  - ru
ID  - DAN_1958_120_5_a1
ER  -