TY  - JOUR
AU  - Mawhin, Jean
TI  - A simple proof of a semi-Fredholm principle for periodically forced systems with homogeneous nonlinearities
JO  - Archivum mathematicum
PY  - 1989
SP  - 235
EP  - 238
VL  - 25
IS  - 4
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/ARM_1989__25_4_a5/
LA  - en
ID  - ARM_1989__25_4_a5
ER  -