%0 Journal Article
%A V. Yu. Shavrukov
%T On two extensions of the logic of provability GL
%J Sbornik. Mathematics
%D 1991
%P 255-270
%V 69
%N 1
%U http://geodesic.mathdoc.fr/item/SM_1991_69_1_a14/
%G en
%F SM_1991_69_1_a14