@article{DAN_1971_197_4_a6,
     author = {I. I. Ibragimov and M.-B. A. Babayev},
     title = {Methods for finding functions deviating least from functions of several variables},
     journal = {Doklady Akademii Nauk},
     pages = {766--769},
     publisher = {mathdoc},
     volume = {197},
     number = {4},
     year = {1971},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1971_197_4_a6/}
}