%0 Journal Article %A A. G. Babenko %T Exact Jackson–Stechkin inequality in the space $L^2(\mathbb R^m)$ %J Trudy Instituta matematiki i mehaniki %D 1998 %P 183-198 %V 5 %U http://geodesic.mathdoc.fr/item/TIMM_1998_5_a13/ %G ru %F TIMM_1998_5_a13