%0 Journal Article
%A N. G. Makarov
%T Stability of the essential spectrum of operators close to a unitary operator
%J Funkcionalʹnyj analiz i ego priloženiâ
%D 1982
%P 72-73
%V 16
%N 3
%I mathdoc
%U http://geodesic.mathdoc.fr/item/FAA_1982_16_3_a15/
%G ru
%F FAA_1982_16_3_a15