%0 Journal Article
%A S. A. Nazarov
%T Threshold resonances and virtual levels in the spectrum of~cylindrical and periodic waveguides
%J Izvestiya. Mathematics 
%D 2020
%P 1105-1160
%V 84
%N 6
%I mathdoc
%U http://geodesic.mathdoc.fr/item/IM2_2020_84_6_a2/
%G en
%F IM2_2020_84_6_a2