%0 Journal Article
%A S. S. Ryshkov
%T On a mapping of a Hilbert space into itself
%J Doklady Akademii Nauk
%D 1961
%P 1042-1044
%V 141
%N 5
%I mathdoc
%U http://geodesic.mathdoc.fr/item/DAN_1961_141_5_a9/
%G ru
%F DAN_1961_141_5_a9