%0 Journal Article %A Mourad Oudghiri %T a-Weyl's theorem and perturbations %J Studia Mathematica %D 2006 %P 193-201 %V 173 %N 2 %I mathdoc %U http://geodesic.mathdoc.fr/articles/10.4064/sm173-2-6/ %R 10.4064/sm173-2-6 %G en %F 10_4064_sm173_2_6