@article{MZM_2013_94_3_a7,
     author = {A. S. Romanyuk},
     title = {Best {Trigonometric} and {Bilinear} {Approximations} of {Classes} of {Functions} of {Several} {Variables}},
     journal = {Matemati\v{c}eskie zametki},
     pages = {401--415},
     publisher = {mathdoc},
     volume = {94},
     number = {3},
     year = {2013},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MZM_2013_94_3_a7/}
}