%0 Journal Article %A P. I. Lizorkin %T Operators connected with fractional differentiation, and classes of differentiable functions %J Trudy Matematicheskogo Instituta imeni V.A. Steklova %D 1972 %P 212-243 %V 117 %I mathdoc %U http://geodesic.mathdoc.fr/item/TM_1972_117_a11/ %G ru %F TM_1972_117_a11