@article{DE_1979_15_6_a1,
     author = {S. V. Zubov},
     title = {The stability of periodic motion},
     journal = {Differencialʹnye uravneni\^a},
     pages = {974--979},
     publisher = {mathdoc},
     volume = {15},
     number = {6},
     year = {1979},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1979_15_6_a1/}
}