@article{IVM_1969_3_a3,
     author = {N. V. Medvedev},
     title = {The method of integral equations in the problem of periodic solutions of ordinary differential equations},
     journal = {Izvesti\^a vys\v{s}ih u\v{c}ebnyh zavedenij. Matematika},
     pages = {28--34},
     year = {1969},
     number = {3},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/IVM_1969_3_a3/}
}