1. See for example Pouget, J.P., Megtert, S. and Comès, R.: 1979, One dimensional conductors “Lecture Notes in Physics” (Springer Verlag) 95, p. 14.
2. Epstein, A.J., Etemad, S., Garito, A.F. and Heeger, A.J.: 1972, Phys. Rev.. B5, p. 952.
3. Pouget, J.P., Megtert, S., Comès, R. and Epstein, A.J.: Phys. Rev. B (in press).
4. Pouget, J.P., Comès, R. and Epstein, A.J.: to be published.
5. Sawatzky, G.A., Huizinga, S. and Kommandeur, J.: 1979, in ref. (1), 96, p. 34.