%0 Journal Article %A Sönke Hansen %T The Leading Singularity of Scattering Kernel for a Transparent Obstacle. %J Mathematische Annalen %D 1987 %P 125-140 %V 279 %N 3 %I mathdoc %U http://geodesic.mathdoc.fr/item/MAN_1987__279_3_164311/ %F MAN_1987__279_3_164311