%0 Journal Article %A Kunio KakiƩ %T A Fundamental Property of Monge Characteristics in Involutive Systems of Non-Linear Partial Differential Equations and its Application. %J Mathematische Annalen %D 1985 %P 89-114 %V 273 %I mathdoc %U http://geodesic.mathdoc.fr/item/MAN_1985__273_164040/ %F MAN_1985__273_164040