A.Klochikhin, V.Yu.Davydov, V.Emtsev, A.Smirnov, and R.v.Baltz
Phys. Stat. Sol. (B) 242, No 7, R58-60 (2005) 12th Int. Symp. "Nanostructures: Physics and Technology", St. Petersburg, Russia, June 21-25,2004