%0 Journal Article
%A V. A. Koibaev
%T On a~question about generalized congruence subgroups.~I
%J Zapiski Nauchnykh Seminarov POMI
%D 2018
%P 105-110
%V 470
%I mathdoc
%U http://geodesic.mathdoc.fr/item/ZNSL_2018_470_a5/
%G ru
%F ZNSL_2018_470_a5