@article{DAN_1991_319_2_a7,
     author = {M. A. Sychev},
     title = {A classical problem of the calculus of variations},
     journal = {Doklady Akademii Nauk},
     pages = {292--295},
     publisher = {mathdoc},
     volume = {319},
     number = {2},
     year = {1991},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1991_319_2_a7/}
}