@article{MZM_1993_53_3_a4,
     author = {V. I. Ivanov},
     title = {On the {Jackson} theorem in~$L_2$ for {Preiss} systems},
     journal = {Matemati\v{c}eskie zametki},
     pages = {37--50},
     publisher = {mathdoc},
     volume = {53},
     number = {3},
     year = {1993},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MZM_1993_53_3_a4/}
}