%0 Journal Article
%A V. I. Burenkov
%T On the additivity of the classes of $W_p^{(r)}(\Omega )$
%J Trudy Matematicheskogo Instituta imeni V.A. Steklova
%D 1967
%P 31-55
%V 89
%I mathdoc
%U http://geodesic.mathdoc.fr/item/TM_1967_89_a3/
%G ru
%F TM_1967_89_a3