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@article{DE_1970_6_12_a0, author = {V. V. Amel'kin and N. A. Lukashevich}, title = {The periods of the solutions of certain autonomous systems}, journal = {Differencialʹnye uravneni\^a}, pages = {2115--2120}, publisher = {mathdoc}, volume = {6}, number = {12}, year = {1970}, language = {ru}, url = {http://geodesic.mathdoc.fr/item/DE_1970_6_12_a0/} }
V. V. Amel'kin; N. A. Lukashevich. The periods of the solutions of certain autonomous systems. Differencialʹnye uravneniâ, Tome 6 (1970) no. 12, pp. 2115-2120. http://geodesic.mathdoc.fr/item/DE_1970_6_12_a0/