@article{MZM_2001_70_4_a14,
     author = {B. S. Kashin},
     title = {Lower {Bounds} for $n${-Term} {Approximations}},
     journal = {Matemati\v{c}eskie zametki},
     pages = {636--638},
     publisher = {mathdoc},
     volume = {70},
     number = {4},
     year = {2001},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MZM_2001_70_4_a14/}
}