@article{MZM_1990_48_4_a16,
     author = {A. A. Yudin and V. A. Yudin},
     title = {On {Jackson's} theorems in~$L_2$},
     journal = {Matemati\v{c}eskie zametki},
     pages = {152--157},
     publisher = {mathdoc},
     volume = {48},
     number = {4},
     year = {1990},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MZM_1990_48_4_a16/}
}