%0 Journal Article %A A. S. Blagoveshchenskii %T Some well-posed problems for the ultrahyperbolic and wave equations with data on the characteristic cone %J Doklady Akademii Nauk %D 1961 %P 990-993 %V 140 %N 5 %I mathdoc %U http://geodesic.mathdoc.fr/item/DAN_1961_140_5_a1/ %G ru %F DAN_1961_140_5_a1