# reference request – \$mathcal{D}_lambda\$ modules \$mathcal{D}_{0}\$ modules equivalence

Fix $$G$$ a finite dimensional reductive group and $$lambda$$ a weight. Apparently the category of $$mathcal{D}_lambda$$ modules on $$G/B$$ is equivalent to $$mathcal{D}_0$$ modules on $$G’/B’$$ for a different group $$G’$$, whose Weyl algebra $$W’$$ are the elements $$win W$$ with $$wlambda-lambda$$ integral. Apparently this is due to Lustzig, where it is covered in the language of monodromic sheaves.

Question: is there a modern reference for this?