%0 Journal Article %A N. Radjabov %T A second-order equation of hyperbolic type with two singular lines %J Differencialʹnye uravneniâ %D 1988 %P 2129-2133 %V 24 %N 12 %I mathdoc %U http://geodesic.mathdoc.fr/item/DE_1988_24_12_a16/ %G ru %F DE_1988_24_12_a16