%0 Journal Article
%A A. B. Ugol'nikov
%T Depth and polynomial equivalence of formulas for closed classes of two-valued logic
%J Matematičeskie zametki
%D 1987
%P 603-612
%V 42
%N 4
%I mathdoc
%U http://geodesic.mathdoc.fr/item/MZM_1987_42_4_a12/
%G ru
%F MZM_1987_42_4_a12