%0 Journal Article %A V. B. Tvorogov %T The sharp front and singularities of solutions of a class of nonhyperbolic equations %J Doklady Akademii Nauk %D 1979 %P 1327-1331 %V 244 %N 6 %I mathdoc %U http://geodesic.mathdoc.fr/item/DAN_1979_244_6_a8/ %G ru %F DAN_1979_244_6_a8