@article{DAN_1991_320_6_a6,
     author = {Kh. P. Rustamov},
     title = {Approximation of functions on a sphere},
     journal = {Doklady Akademii Nauk},
     pages = {1319--1325},
     year = {1991},
     volume = {320},
     number = {6},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1991_320_6_a6/}
}