TY  - JOUR
AU  - A. Raouf Chouikha
TI  - Monotonicity of the period function for
 some planar differential systems.
 Part I: Conservative and quadratic systems
JO  - Applicationes Mathematicae
PY  - 2005
SP  - 305
EP  - 325
VL  - 32
IS  - 3
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/articles/10.4064/am32-3-5/
DO  - 10.4064/am32-3-5
LA  - en
ID  - 10_4064_am32_3_5
ER  -