1. see refs. 1–6 in R. G. Mani, Phys. Rev. B 41, 7922 (1990).
2. see The Quantum Hall Effect, ed. R. Prange and S. Girvin, (Springer-Verlag, New York, 1987).
3. J. B. Choi, Ph.D Thesis, Univ. of Maryland, 1989 (unpublished).
4. W. S. Boyle and A. Brailsford, Phys. Rev. 107, 903 (1957).
5. For InSb (Hg0.8Cd0.2Te), R*∼ 0.7meV (0.3meV).