@article{DAN_1991_321_1_a3,
     author = {Kh. P. Rustamov},
     title = {On the equivalence of some moduli of smoothness on a sphere},
     journal = {Doklady Akademii Nauk},
     pages = {23--27},
     year = {1991},
     volume = {321},
     number = {1},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1991_321_1_a3/}
}