@article{01780382, title = {Center conditions for a simple class of quintic systems.}, journal = {International Journal of Mathematics and Mathematical Sciences}, volume = {30}, year = {2002}, pages = {625-632}, doi = {10.1155/S0161171202012802}, zbl = {1008.34023}, language = {en}, url = {http://dml.mathdoc.fr/item/01780382} }
Volokitin, Evgenii P. Center conditions for a simple class of quintic systems.. International Journal of Mathematics and Mathematical Sciences, Tome 30 (2002) pp. 625-632. doi : 10.1155/S0161171202012802. http://gdmltest.u-ga.fr/item/01780382/