@article{IM2_1988_30_3_a7,
     author = {S. M. Nikol'skii and P. I. Lizorkin},
     title = {Approximation of functions on the sphere},
     journal = {Izvestiya. Mathematics },
     pages = {599--614},
     publisher = {mathdoc},
     volume = {30},
     number = {3},
     year = {1988},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/IM2_1988_30_3_a7/}
}