@article{DE_1989_25_11_a32,
     author = {A. S. Shube},
     title = {Sufficient conditions for the center for a two-dimensional autonomous system with cubic right-hand sides},
     journal = {Differencialʹnye uravneni\^a},
     pages = {2014--2016},
     publisher = {mathdoc},
     volume = {25},
     number = {11},
     year = {1989},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1989_25_11_a32/}
}