%0 Journal Article
%A V. P. Elizarov
%T Equivalent definitions of a perfect system and some of its properties
%J Matematičeskie zametki
%D 1981
%P 335-350
%V 29
%N 3
%I mathdoc
%U http://geodesic.mathdoc.fr/item/MZM_1981_29_3_a1/
%G ru
%F MZM_1981_29_3_a1