%0 Journal Article %A D. R. Yafaev %T The virial theorem and conditions for wave operators to be unitary in scattering by a~nonstationary potential %J Trudy Matematicheskogo Instituta imeni V.A. Steklova %D 1983 %P 210-217 %V 159 %I mathdoc %U http://geodesic.mathdoc.fr/item/TM_1983_159_a13/ %G ru %F TM_1983_159_a13