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@article{DE_1986_22_9_a7, author = {M. N. Popa and K. S. Sibirskii}, title = {Focal cyclicity of critical points of a differential system}, journal = {Differencialʹnye uravneni\^a}, pages = {1539--1545}, publisher = {mathdoc}, volume = {22}, number = {9}, year = {1986}, language = {ru}, url = {http://geodesic.mathdoc.fr/item/DE_1986_22_9_a7/} }
M. N. Popa; K. S. Sibirskii. Focal cyclicity of critical points of a differential system. Differencialʹnye uravneniâ, Tome 22 (1986) no. 9, pp. 1539-1545. http://geodesic.mathdoc.fr/item/DE_1986_22_9_a7/