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@article{IVM_1972_9_a13, author = {E. G. Sadovnikov}, title = {A~certain criterion for the absence of limit cycles}, journal = {Izvesti\^a vys\v{s}ih u\v{c}ebnyh zavedenij. Matematika}, pages = {95--98}, publisher = {mathdoc}, number = {9}, year = {1972}, language = {ru}, url = {http://geodesic.mathdoc.fr/item/IVM_1972_9_a13/} }
E. G. Sadovnikov. A~certain criterion for the absence of limit cycles. Izvestiâ vysših učebnyh zavedenij. Matematika, no. 9 (1972), pp. 95-98. http://geodesic.mathdoc.fr/item/IVM_1972_9_a13/