%0 Journal Article
%A Yu. B. Orochko
%T Impenetrability condition for a~degenerate point of a~one-term  symmetric differential operator of even order
%J Sbornik. Mathematics
%D 2003
%P 745-774
%V 194
%N 5
%I mathdoc
%U http://geodesic.mathdoc.fr/item/SM_2003_194_5_a4/
%G en
%F SM_2003_194_5_a4