%0 Journal Article
%A E. Z. Dyment
%T Exact bounds of denumerable collections of degrees of difficulty
%J Matematičeskie zametki
%D 1980
%P 899-910
%V 28
%N 6
%I mathdoc
%U http://geodesic.mathdoc.fr/item/MZM_1980_28_6_a8/
%G ru
%F MZM_1980_28_6_a8