@article{DE_1986_22_5_a27,
     author = {I. P. Makarov},
     title = {Alpha-regular limit cycles},
     journal = {Differencialʹnye uravneni\^a},
     pages = {900--902},
     year = {1986},
     volume = {22},
     number = {5},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1986_22_5_a27/}
}