@article{MZM_1988_43_5_a1,
     author = {Yu. A. Kaz'min},
     title = {Approximate properties in $L_2$ of certain functional sequences},
     journal = {Matemati\v{c}eskie zametki},
     pages = {593--603},
     publisher = {mathdoc},
     volume = {43},
     number = {5},
     year = {1988},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MZM_1988_43_5_a1/}
}