%0 Journal Article
%A V. L. Selivanov
%T Fine hierarchy of formulas
%J Algebra i logika
%D 1991
%P 568-582
%V 30
%N 5
%I mathdoc
%U http://geodesic.mathdoc.fr/item/AL_1991_30_5_a4/
%G ru
%F AL_1991_30_5_a4