1. Allen, S.J.Jr., Tsui, D.C., and Logan, R.A. (1977). Phys. Rev. Lett. 38:980.
2. Ashcroft, N.W. and Mermin, N.D. (1976). Solid State Physics. New York: Holt, Rinehart and Winston.
3. Baeriswyl, D. and Maki, K. (1985). Phys. Rev. B 31:6633.
4. Bardeen, J., Cooper, L.N., and Schrieffer, J.R. (1957). Phys. Rev. 106:162; 108: 1175.
5. Becca, F., Tarquini, M., Grilli, M., and Di Castro, C. (1996). Phys. Rev. B 54:12443.