%0 Journal Article
%A A. V. Bitsadze
%T On the question of formulating the characteristic problem for second order hyperbolic systems
%J Doklady Akademii Nauk
%D 1975
%P 1289-1292
%V 223
%N 6
%I mathdoc
%U http://geodesic.mathdoc.fr/item/DAN_1975_223_6_a0/
%G ru
%F DAN_1975_223_6_a0