1. For example Proceedings of 19th International Conference on Low Temperature Physics Brighton 1990 Physica B 165 & 166 1990
2. Spin polaron mechanism for the superconductivity in oxide compounds has been proposed and investigated theoretically by H. Kamimura and his coworkers. H. Kamimura, Proceedings of of the Adriatico Conference on Theoretical Understanding of High Temperature Superconductivity, Trieste (1988), p. 163, World Scientific, Singapore (1989); H. Kamimura, S. Matsuno and R. Saito: 1988, Solid State Commun. 67, 363; H. Kamimura, S. Matsuno and R. Saito, Mechanisms of High Temperature Superconductivity, Vol. 11 of Springer Series in Material Science, H. Kamimura and A. Oshiyama (eds.), Springer, Heidelberg (1989), p. 8.; H. Kamimura, S. Matsuno and K. Ishida: 1989, Physica C
162-164, 781; M. Eto, R. Saito and H. Kamimura: 1989, Solid State Commun. 71, 425; K. Ishida and H. Kamimura: 1990, Phys. Rev. B
42, 8312; H. Kamimura and M. Eto: 1990, J. Phys. Soc. Jpn. 59, 3053; T. Shimizu and H. Kamimura: 1990, J. Phys. Soc. Jpn. 59, 3691; The problem of coexistence of magnetic correlation and superconductivity is also discussed in A. Ohta, M. Nojima, T. Suzuki and Y. Natsume: 1989, J. Phys. Soc. Jpn. 58, 4147 and references therein.
3. For example, T. Oguchi, The Statistical Theory of Magnetic Materials, Shoukabou, Tokyo (1970).
4. One of the most noteworthy work is S. Liang, B. Doucot and P.W. Anderson: 1988, Phys. Rev. Lett. 61, 365; we would like to point out that the criticism on this work is offered by D.A. Huse and V. Elser: 1988, Phys. Rev. Lett. 60, 2531.
5. For example, S. Miyashita: 1988, J. Phys. Soc. Jpn. 57, 1934; Y. Okabe and M. Kikuchi: 1988, J. Phys. Soc. Jpn. 57, 4351; M. Kikuchi and Y. Okabe: 1989, J. Phys. Soc. Jpn. 58, 679; J.D. Reger and A.P. Young: 1988, Phys. Rev. B
37, 5478; J.D. Reger, J.A. Riera and A.P. Young: 1989, J. Phys.: Condens. Matter
1, 1855; D.A. Huse: 1988, Phys. Rev. B
37, 2380; M. Gross, E. Sanches. Velasca and E. Siggia: 1989, Phys. Rev. B
39, 2484; G. Gomez-Santos, J.D. Joannopoulos and J.W. Negele: 1989, Phys. Rev. B
39, 4435.