%0 Journal Article %A Werner Ricker %T A Criterion for an Operator with Real Spectrum to Be of Scalar-type. %J Monatshefte für Mathematik %D 1983 %P 229-234 %V 95 %I mathdoc %U http://geodesic.mathdoc.fr/item/MOMA_1983__95_178122/ %F MOMA_1983__95_178122