%0 Journal Article
%A M. A. Chahkiev
%T Linear differential operators with real spectrum, and optimal quadrature formulas
%J Izvestiya. Mathematics 
%D 1985
%P 391-417
%V 25
%N 2
%I mathdoc
%U http://geodesic.mathdoc.fr/item/IM2_1985_25_2_a6/
%G en
%F IM2_1985_25_2_a6