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@article{DE_1982_18_5_a14, author = {L. A. Cherkas}, title = {On the question of the analyticity of a manifold that defines limit cycles}, journal = {Differencialʹnye uravneni\^a}, pages = {839--845}, publisher = {mathdoc}, volume = {18}, number = {5}, year = {1982}, language = {ru}, url = {http://geodesic.mathdoc.fr/item/DE_1982_18_5_a14/} }
L. A. Cherkas. On the question of the analyticity of a manifold that defines limit cycles. Differencialʹnye uravneniâ, Tome 18 (1982) no. 5, pp. 839-845. http://geodesic.mathdoc.fr/item/DE_1982_18_5_a14/