@article{MZM_1992_52_3_a13,
     author = {Kh. P. Rustamov},
     title = {Equivalence of $K$-functional and modulus of smoothness of functions on the sphere},
     journal = {Matemati\v{c}eskie zametki},
     pages = {123--129},
     publisher = {mathdoc},
     volume = {52},
     number = {3},
     year = {1992},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MZM_1992_52_3_a13/}
}