%0 Journal Article %A F. Malikow %T Singular vectors corresponding to imaginary roots in verma modules over affine Lie algebras. %J Mathematica Scandinavica %D 1990 %P 73-90 %V 66 %N 1 %I mathdoc %U http://geodesic.mathdoc.fr/item/MS2_1990__66_1_167094/ %F MS2_1990__66_1_167094