@article{MZM_1986_39_5_a3,
     author = {A. G. Babenko},
     title = {The exact constant in the {Jackson} inequality in $L^2$},
     journal = {Matemati\v{c}eskie zametki},
     pages = {651--664},
     publisher = {mathdoc},
     volume = {39},
     number = {5},
     year = {1986},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MZM_1986_39_5_a3/}
}