%0 Journal Article
%A I. M. Petrov
%T On the order of approximation of functions of class $Z_1$ by positive linear polynomial operators
%J Trudy Matematicheskogo Instituta imeni V.A. Steklova
%D 1964
%V 19
%N 2
%I mathdoc
%U http://geodesic.mathdoc.fr/item/RM_1964_19_2_a7/
%G ru
%F RM_1964_19_2_a7