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@article{DE_1973_9_8_a7, author = {L. A. Cherkas}, title = {The cycles of the equation $y'=Q_2(x,y)/P_2(x,y)$}, journal = {Differencialʹnye uravneni\^a}, pages = {1432--1437}, publisher = {mathdoc}, volume = {9}, number = {8}, year = {1973}, language = {ru}, url = {http://geodesic.mathdoc.fr/item/DE_1973_9_8_a7/} }
L. A. Cherkas. The cycles of the equation $y'=Q_2(x,y)/P_2(x,y)$. Differencialʹnye uravneniâ, Tome 9 (1973) no. 8, pp. 1432-1437. http://geodesic.mathdoc.fr/item/DE_1973_9_8_a7/