@article{DAN_1991_316_3_a8,
     author = {N. K. Rakhmetov},
     title = {Uniqueness of the element of best approximation in some function},
     journal = {Doklady Akademii Nauk},
     pages = {553--557},
     publisher = {mathdoc},
     volume = {316},
     number = {3},
     year = {1991},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1991_316_3_a8/}
}