Voir la notice de l'article provenant de la source Math-Net.Ru
@article{DE_1981_17_5_a23, author = {A. A. Samodurov}, title = {Problem of the center and the integrating factor for a {Li\'enard} equation}, journal = {Differencialʹnye uravneni\^a}, pages = {936--940}, publisher = {mathdoc}, volume = {17}, number = {5}, year = {1981}, language = {ru}, url = {http://geodesic.mathdoc.fr/item/DE_1981_17_5_a23/} }
A. A. Samodurov. Problem of the center and the integrating factor for a Li\'enard equation. Differencialʹnye uravneniâ, Tome 17 (1981) no. 5, pp. 936-940. http://geodesic.mathdoc.fr/item/DE_1981_17_5_a23/