@article{DE_1988_24_9_a21,
     author = {V. G. Compel},
     title = {Sufficient conditions for the center for a two-dimensional autonomous system whose right-hand sides are polynomials of the third degree},
     journal = {Differencialʹnye uravneni\^a},
     pages = {1636--1637},
     publisher = {mathdoc},
     volume = {24},
     number = {9},
     year = {1988},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1988_24_9_a21/}
}