1. J. G. Bednorz and K. A. Müller, Z. Phys. B64, 189 (1986).
2. See e.g. Proc. Los Alamos Symposium 1989 on High Temperature Superconductivity, K. S. Bedell, D. Coffey, D. E. Meltzer, D. Pines and J. R. Schrieffer eds., Addison-Wesley Publishing Co., 1990.
3. For a short overview, see e.g. B. Batlogg, Physics Today, June 1991, p. 44; also in “Physics of High-Temperature Superconductors,” eds. S. Maekawa and M. Sato, p. 219, Springer Series in Solid-State Sciences, Vol. 106, Springer-Verlag 1992; also in Ref. 2, p 37–82.
4. P. A. Lee, Ref. 2, p. 96–116.
5. K. Levin, Ju H. Kim, J. P. Lu and Aimioro Si; Physica C 175, 449 (1991).