D-branes in curved spacetime: Nappi-Witten background
  We find exact D-brane configurations in the Nappi-Witten background using the boundary state approach and describe how they are related by T-duality transformations. We also show that the classical boundary conditions of the associated sigma model correspond to a field dependent automorphism relating the chiral currents and discuss the correspondence between the boundary state approach and the sigma model approach. 
Sonia Stanciu, Arkady Tseytlin