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@article{IVM_1963_4_a13, author = {N. V. Medvedev}, title = {On limit cycles}, journal = {Izvesti\^a vys\v{s}ih u\v{c}ebnyh zavedenij. Matematika}, pages = {99--103}, publisher = {mathdoc}, number = {4}, year = {1963}, language = {ru}, url = {http://geodesic.mathdoc.fr/item/IVM_1963_4_a13/} }
N. V. Medvedev. On limit cycles. Izvestiâ vysših učebnyh zavedenij. Matematika, no. 4 (1963), pp. 99-103. http://geodesic.mathdoc.fr/item/IVM_1963_4_a13/