%0 Journal Article
%A G. Sh. Fridman
%T Radially critical directed graphs
%J Doklady Akademii Nauk
%D 1973
%P 565-568
%V 212
%N 3
%I mathdoc
%U http://geodesic.mathdoc.fr/item/DAN_1973_212_3_a10/
%G ru
%F DAN_1973_212_3_a10