@article{DE_1974_10_4_a4,
     author = {G. M. Buldyk},
     title = {The number of {Ljapunov} constants for the conditions of the center of a certain differential equation},
     journal = {Differencialʹnye uravneni\^a},
     pages = {606--612},
     publisher = {mathdoc},
     volume = {10},
     number = {4},
     year = {1974},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1974_10_4_a4/}
}