%0 Journal Article
%A V. L. Selivanov
%T Difference Hierarchy in $\varphi$-Spaces
%J Algebra i logika
%D 2004
%P 425-444
%V 43
%N 4
%I mathdoc
%U http://geodesic.mathdoc.fr/item/AL_2004_43_4_a2/
%G ru
%F AL_2004_43_4_a2