@article{DE_1975_11_2_a8,
     author = {Yu. A. Ryabov and M. F. Korolev},
     title = {The construction of periodic solutions of certain linear and quasilinear equations},
     journal = {Differencialʹnye uravneni\^a},
     pages = {280--286},
     publisher = {mathdoc},
     volume = {11},
     number = {2},
     year = {1975},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1975_11_2_a8/}
}