%0 Journal Article %A F. I. Frankl' %T Theorem of existence of weak solution of direct problem of of plane-parallel Laval nozzle to a first approximation %J Trudy Matematicheskogo Instituta imeni V.A. Steklova %D 1960 %V 15 %N 1 %U http://geodesic.mathdoc.fr/item/RM_1960_15_1_a23/ %G ru %F RM_1960_15_1_a23