TY - JOUR AU - V. I. Burenkov TI - The approximation of functions in the space $W_p^r(\Omega )$ by compactly supported functions for an arbitrary open set~$\Omega $ JO - Trudy Matematicheskogo Instituta imeni V.A. Steklova PY - 1974 SP - 51 EP - 63 VL - 131 PB - mathdoc UR - http://geodesic.mathdoc.fr/item/TM_1974_131_a5/ LA - ru ID - TM_1974_131_a5 ER -