%0 Journal Article
%A Yu. L. Ershov
%T A certain hierarchy of sets. III
%J Algebra i logika
%D 1970
%P 34-51
%V 9
%N 1
%I mathdoc
%U http://geodesic.mathdoc.fr/item/AL_1970_9_1_a2/
%G ru
%F AL_1970_9_1_a2