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@article{DAN_1965_165_2_a0, author = {P. G. Aizengendler and M. M. Vainberg}, title = {On periodic solutions of non-autonomous systems}, journal = {Doklady Akademii Nauk}, pages = {255--257}, publisher = {mathdoc}, volume = {165}, number = {2}, year = {1965}, language = {ru}, url = {http://geodesic.mathdoc.fr/item/DAN_1965_165_2_a0/} }
P. G. Aizengendler; M. M. Vainberg. On periodic solutions of non-autonomous systems. Doklady Akademii Nauk, Tome 165 (1965) no. 2, pp. 255-257. http://geodesic.mathdoc.fr/item/DAN_1965_165_2_a0/