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@article{DAN_1967_172_2_a3, author = {Yu. S. Kolesov}, title = {Positive periodic solutions of a class of differential equations of second order}, journal = {Doklady Akademii Nauk}, pages = {264--266}, publisher = {mathdoc}, volume = {172}, number = {2}, year = {1967}, language = {ru}, url = {http://geodesic.mathdoc.fr/item/DAN_1967_172_2_a3/} }
Yu. S. Kolesov. Positive periodic solutions of a class of differential equations of second order. Doklady Akademii Nauk, Tome 172 (1967) no. 2, pp. 264-266. http://geodesic.mathdoc.fr/item/DAN_1967_172_2_a3/