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@article{DE_1969_5_3_a16, author = {V. M. Lebedeva}, title = {The number of periodic solutions of a first order equation with rational right hand side}, journal = {Differencialʹnye uravneni\^a}, pages = {560--562}, publisher = {mathdoc}, volume = {5}, number = {3}, year = {1969}, language = {ru}, url = {http://geodesic.mathdoc.fr/item/DE_1969_5_3_a16/} }
V. M. Lebedeva. The number of periodic solutions of a first order equation with rational right hand side. Differencialʹnye uravneniâ, Tome 5 (1969) no. 3, pp. 560-562. http://geodesic.mathdoc.fr/item/DE_1969_5_3_a16/