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@article{DAN_1965_160_2_a9, author = {A. I. Fet}, title = {On a periodicity problem in the calculus of variations}, journal = {Doklady Akademii Nauk}, pages = {287--289}, publisher = {mathdoc}, volume = {160}, number = {2}, year = {1965}, language = {ru}, url = {http://geodesic.mathdoc.fr/item/DAN_1965_160_2_a9/} }
A. I. Fet. On a periodicity problem in the calculus of variations. Doklady Akademii Nauk, Tome 160 (1965) no. 2, pp. 287-289. http://geodesic.mathdoc.fr/item/DAN_1965_160_2_a9/