@article{MZM_1990_48_6_a1,
     author = {M.-B. Babayev},
     title = {Approximation of {Sobolev} classes of functions by sums of products of functions of fewer variables},
     journal = {Matemati\v{c}eskie zametki},
     pages = {10--21},
     publisher = {mathdoc},
     volume = {48},
     number = {6},
     year = {1990},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MZM_1990_48_6_a1/}
}