Kopaev Y.V. , Belyavsky V.I. , Pomerantsev Y.A. Resistanse of biased quantum well systems. Phys.Low-Dim.Struct. , N1/2 , с. P.1-10 , 01.1997 Kopaev Y.V. , Belyavsky V.I. , Shevtsov S.V. , Kornyakov N.V. , Pomerantsev Y.A. Deep impurity states in semiconductor quantum well structures. Semiconductor Sci. & Technol. , Vol.13 , с. P.460-467 , 01.1998