1. See, for instance, M. Gaudin, La fonction d’onde de Bethe (Masson, Paris, 1983).
2. See, for instance, J. P. Pouget, in Low-Dimensional Conductors and Superconductors, edited by D. Jerome and L. Caron (Plenum, New York, 1987).
3. V. J. Emery, in Highly Conducting One-Dimensional Solids, edited by J. T. Devreese et al. (Plenum, New York, 1979).
4. J. Solyom, Adv. Phys. 28, 201 (1979).
5. P. W. Anderson, Phys. Rev. Lett. 64, 1839 (1990); 65, 2306 (1990).