@article{MZM_2011_89_4_a3,
     author = {T. V. Iofina},
     title = {On the {Order} of {Approximation} by {Riesz} {Means} in {Multiplicative} {Systems} in the {Classes~}$E_X[\varepsilon]$},
     journal = {Matemati\v{c}eskie zametki},
     pages = {508--523},
     publisher = {mathdoc},
     volume = {89},
     number = {4},
     year = {2011},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MZM_2011_89_4_a3/}
}