Voir la notice de l'article provenant de la source Math-Net.Ru
@article{DE_1985_21_3_a18, author = {N. S. Berezkina}, title = {Classes of third-order systems without moving critical points}, journal = {Differencialʹnye uravneni\^a}, pages = {517--520}, publisher = {mathdoc}, volume = {21}, number = {3}, year = {1985}, language = {ru}, url = {http://geodesic.mathdoc.fr/item/DE_1985_21_3_a18/} }
N. S. Berezkina. Classes of third-order systems without moving critical points. Differencialʹnye uravneniâ, Tome 21 (1985) no. 3, pp. 517-520. http://geodesic.mathdoc.fr/item/DE_1985_21_3_a18/