%0 Journal Article
%A M. Sh. Birman
%T On existence conditions for wave operators
%J Doklady Akademii Nauk
%D 1962
%P 506-509
%V 143
%N 3
%I mathdoc
%U http://geodesic.mathdoc.fr/item/DAN_1962_143_3_a2/
%G ru
%F DAN_1962_143_3_a2