@article{DE_1999_35_8_a2,
     author = {S. M. Dzyuba},
     title = {On conditionally periodic solutions of differential equations},
     journal = {Differencialʹnye uravneni\^a},
     pages = {1020--1023},
     publisher = {mathdoc},
     volume = {35},
     number = {8},
     year = {1999},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1999_35_8_a2/}
}