%0 Journal Article %A F. I. Frankl' %T Existence of a weak solution to the direct problem in the theory of sonic flow past a profile in first approximation %J Doklady Akademii Nauk %D 1960 %P 789-792 %V 132 %N 4 %I mathdoc %U http://geodesic.mathdoc.fr/item/DAN_1960_132_4_a14/ %G ru %F DAN_1960_132_4_a14