@article{DAN_1969_184_3_a8,
     author = {N. V. Medvedev},
     title = {Periodic solutions of differential equations in a {Banach} space},
     journal = {Doklady Akademii Nauk},
     pages = {542--545},
     publisher = {mathdoc},
     volume = {184},
     number = {3},
     year = {1969},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1969_184_3_a8/}
}