@article{DE_2006_42_1_a1,
     author = {Yu. L. Bondar and A. P. Sadovskii},
     title = {Solution of the center-focus problem for a cubic system reducible to a lienard system},
     journal = {Differencialʹnye uravneni\^a},
     pages = {11--22},
     publisher = {mathdoc},
     volume = {42},
     number = {1},
     year = {2006},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_2006_42_1_a1/}
}