TY - JOUR AU - P. I. Lizorkin TI - Classes of functions constructed on the basis of averages over spheres. (The case of spaces of Sobolev type) JO - Trudy Matematicheskogo Instituta imeni V.A. Steklova PY - 1990 SP - 122 EP - 139 VL - 192 PB - mathdoc UR - http://geodesic.mathdoc.fr/item/TM_1990_192_a10/ LA - ru ID - TM_1990_192_a10 ER -