TY  - JOUR
AU  - L. A. Cherkas
AU  - A. A. Grin'
TI  - Spline approximations in the problem of estimating the number of limit cycles of autonomous systems on the plane
JO  - Differencialʹnye uravneniâ
PY  - 2006
SP  - 213
EP  - 220
VL  - 42
IS  - 2
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/DE_2006_42_2_a8/
LA  - ru
ID  - DE_2006_42_2_a8
ER  -