1. NATO Adv. Sci. Inst. Ser. B,1987
2. NATO Adv. Sci. Inst. Ser. B;D. Heitmann,1987
3. See, e.g., A. Pinczuk and G. Abstreiter in “Light Scattering in Solids V”, M. Cardona and G. Güntherodt (eds.), (Springer, Berlin, 1989) p. 153; A. Pinczuk in “Advances in Solid State Physics”, Vol. 32 (Vieweg, Braunschweig, 1992) p. 45.
4. NATO Adv. Sci. Inst. Ser. B 170;C. Weisbuch,1987
5. C.H. Chang, S.A. Lyon, and C.W. Tu, Appl. Phys. Lett. 53, 258 (1988).