%0 Journal Article
%A A. Yu. Ol'shanskii
%T On characteristic subgroups of free groups
%J Trudy Matematicheskogo Instituta imeni V.A. Steklova
%D 1974
%V 29
%N 1
%I mathdoc
%U http://geodesic.mathdoc.fr/item/RM_1974_29_1_a20/
%G ru
%F RM_1974_29_1_a20