@article{DE_1987_23_3_a31,
     author = {O. A. Ivanov and G. R. Kudryashova},
     title = {On the smoothness of an invariant surface of a quasihomogeneous system in the neighborhood of a simple exceptional direction},
     journal = {Differencialʹnye uravneni\^a},
     pages = {540--543},
     publisher = {mathdoc},
     volume = {23},
     number = {3},
     year = {1987},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1987_23_3_a31/}
}