Voir la notice de l'article provenant de la source Math-Net.Ru
@article{DE_1991_27_11_a7, author = {D. S. Ushkho}, title = {Limit cycles of an autonomous system with algebraic right-hand sides}, journal = {Differencialʹnye uravneni\^a}, pages = {1915--1925}, publisher = {mathdoc}, volume = {27}, number = {11}, year = {1991}, language = {ru}, url = {http://geodesic.mathdoc.fr/item/DE_1991_27_11_a7/} }
D. S. Ushkho. Limit cycles of an autonomous system with algebraic right-hand sides. Differencialʹnye uravneniâ, Tome 27 (1991) no. 11, pp. 1915-1925. http://geodesic.mathdoc.fr/item/DE_1991_27_11_a7/