%0 Journal Article
%A N. B. Kerimov
%T Necessary conditions for the property of being a basis in $L_2(G)$ for a system of eigen- and associated functions of a second-order
%J Doklady Akademii Nauk
%D 1988
%P 809-811
%V 299
%N 4
%I mathdoc
%U http://geodesic.mathdoc.fr/item/DAN_1988_299_4_a8/
%G ru
%F DAN_1988_299_4_a8