%0 Journal Article
%A B. R. Lavruk
%T The index of a boundary problem operator for an elliptical system of second order linear differential equations, 

%J Doklady Akademii Nauk
%D 1958
%P 970-972
%V 121
%N 6
%I mathdoc
%U http://geodesic.mathdoc.fr/item/DAN_1958_121_6_a3/
%G ru
%F DAN_1958_121_6_a3