@article{DE_1982_18_5_a21,
     author = {A. B. Vasil'eva},
     title = {On the theory of periodic solutions of partial differential equations with small parameters},
     journal = {Differencialʹnye uravneni\^a},
     pages = {889--892},
     publisher = {mathdoc},
     volume = {18},
     number = {5},
     year = {1982},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1982_18_5_a21/}
}