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@article{DE_1982_18_5_a4, author = {\`E. I. Grudo}, title = {Periodic solutions of periodic differential systems in the general critical case}, journal = {Differencialʹnye uravneni\^a}, pages = {763--767}, publisher = {mathdoc}, volume = {18}, number = {5}, year = {1982}, language = {ru}, url = {http://geodesic.mathdoc.fr/item/DE_1982_18_5_a4/} }
È. I. Grudo. Periodic solutions of periodic differential systems in the general critical case. Differencialʹnye uravneniâ, Tome 18 (1982) no. 5, pp. 763-767. http://geodesic.mathdoc.fr/item/DE_1982_18_5_a4/