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@article{IVM_1970_11_a10, author = {P. P. Rybin}, title = {The periodic solutions of differential equations in a~particular case}, journal = {Izvesti\^a vys\v{s}ih u\v{c}ebnyh zavedenij. Matematika}, pages = {97--99}, publisher = {mathdoc}, number = {11}, year = {1970}, language = {ru}, url = {http://geodesic.mathdoc.fr/item/IVM_1970_11_a10/} }
P. P. Rybin. The periodic solutions of differential equations in a~particular case. Izvestiâ vysših učebnyh zavedenij. Matematika, no. 11 (1970), pp. 97-99. http://geodesic.mathdoc.fr/item/IVM_1970_11_a10/