%0 Journal Article %A S. N. Kudryavtsev %T Approximation of the derivatives of finitely smooth functions belonging to non-isotropic classes %J Izvestiya. Mathematics %D 2004 %P 77-123 %V 68 %N 1 %I mathdoc %U http://geodesic.mathdoc.fr/item/IM2_2004_68_1_a3/ %G en %F IM2_2004_68_1_a3