7 [1] K. Tanaka et al. , Science 314 , 1914 (2006). [2] T. Valla et al. , Science 314 , 1910 (2006). [3] A.J. Millis, Science 314 , 1888 (2006). [4] H.B. Yang, J.D. Rameau, P.D. Johnson, T. Valla, and G.D. Gu, Nature 456 77 (2008). [5] Gweon G.-H., Sasagawa T., Zhou S. Y., Graf J., Takagi, H., Lee D.-H., and Lanzara A., Science 430 , 187 (2004) [6] H. Won, and K. Maki, Phys. Rev. B 49 , 1397 (1994); K. Maki, and H. Won, J. Phys. I (France) 6 , 2317 (1996) [7] M. Le Tacon et al. , Nature Phys. 2 , 537 (2006). [8] C. Panagopoulos, J.R. Cooper, and T. Xiang, Phys. Rev. B 57 , 13422 (1998); C. Panagapoulos, and T. Xiang, Phys. Rev. Lett. 81 , 2336 (1998) [9] D.M. Broun, W.A. Huttema, P.J. Turner, S. ¨ Oscan, B. Morgan, R. Liang, W.N. Hardy, and D.A. Bonn, Phys. Rev. Lett. 99 , 237003-1 (2007). [10] K.A. M¨ uller, Phil. Mag. Lett. 82 , 279 (2002). [11] D.R. Harshman, W.J. Kossler, X. Wan, A.T. Fiory, A.J. Greer, E. Koster, and J.D. Dow, Phys. Rev. B 69 , 174505 (1-13) (2004). [12] R.A. Klemm, Phil. Mag. 85 , 801 (2005). [13] E.A. Pashitiskii, V.I. Pentegov, and A.V. Semenov, Phys- ica C 282-287 , 1843 (1997). [14] S. Fujita and S. Godoy, Theory of High Temperature Superconductivity (Kluwer Academic Publishers, Dor- drecht, 2002) [15] G.B. Arnold and R.A. Klemm, Phil. Mag. 86 , 2811 (2006). [16] C.C. Tseui and J.R. Kirtley, Revs. Mod. Phys. 72 , 969 (2000). [17] M. Ichioka, A. Hasegawa, and K. Machida, Phys. Rev. B 59 , 184 (1999). [18] R.A. Klemm, priv. comm. [19] T. Dahm et al., Nature Physics 5 , 217 (2009). [20] Y.J. Uemura et al. , Phys. Rev. Lett. 62 , 2317 (1989); Phys. Rev. Lett. 66 , 2665 (1991); Y.J. Uemura, J. Phys.: Condens. Matter 16 , S4515 (2004). [21] Y.J. Uemura, Physica B 374-375 , 1 (2006). [22] M. Casas, A.Rigo, M. de Llano, O. Rojo, and M.A. Sol´ıs, Phys. Lett. A 245 , 55 (1998); M. Casas, S. Fujita, M. de Llano, A. Puente, A. Rigo, and M.A. Sol´ıs, Physica C 295 , 93 (1998). [23] S. Fujita, K. Ito, and S. Godoy, Quantum Theory of Con- ducting Matter: Superconductivity (Springer-Verlag, Hei- delberg, 2009). [24] M. de Llano and J.F. Annett, Int. J. Mod. Phys. B 21 3657 (2007). [46] C. Villarreal and M. de Llano, to be published in Proceed- ings of the Ninth Conference on Quantum Field Theory under the Infuence of External Conditions (World Scien- tific, 2009). Now on arXiv:0912.1563v1 [45] Physical Properties of High Temperature Superconductors III , Ed. by D.M. Ginsberg (World Scientific, Singapore, 1992). [44] T. Hasegawa et al ., Japanese J. Appl. Physics 28 , L 179 (1989). [43] D.R. Harshman and P. Mills, Jr., Phys. Rev. B 45 , 10684 (1992). [42] R. Liang, D.A. Bonn, and W.N. Hardy, Phys. Rev. B 93 , 180505 (2006). [41] T. Pereg-Barnea et al. , Phys. Rev. B 69 , 184513 (2004). [40] W.E. Pickett, Rev. Mod. Phys. 61 , 433 (1989) [25] J. Bardeen, L.N. Cooper, and J.R. Schrieffer, Phys. Rev. 106 , 162 (1957); 108 , 1175 (1957). [26] J.R. Schrieffer, Theory of Superconductivity (W.A. Ben- jamin, Reading, MA, 1964) p. 33. [27] L.N. Cooper, Phys. Rev. 104 , 1189 (1956). [28] K. Miyake, Prog. Theor. Phys. 69 , 1794 (1983). [29] P. Gosdzinsky and R. Tarrach, Am. J. Phys. 59 , 70 (1991). [30] S.K. Adhikari, M. Casas, A. Puente, A. Rigo, M. Fortes, M.A. Sol´ıs, M. de Llano, A.A. Valladares, and O. Rojo, Phys. Rev. B 62 , 8671 (2000). [31] M. Casas, S. Fujita, M. de Llano, A. Puente, A. Rigo, M.A. Sol´ıs, Physica C 295 , 93 (1998). [32] P.C. Hohenberg, Phys. Rev. 158 , 383 (1967). [33] M. de Llano and J.J. Valencia, Mod. Phys. Lett. B 20 , 1067 (2006). [34] P.W. Anderson and P. Morel, Phys. Rev. 123 , 1911 (1961). [35] P.J. Hirschfeld and N. Goldenfeld, Phys. Rev. B 48 , 4219 (1993). [36] E. Schachinger, J.J. Tu, and J.P. Carbotte, Phys. Rev. B 67 , 214508 (2003); E. Schachinger, and J.P. Carbotte, J. of Phys. Studies 7 , 209 (2003); Phys. Rev. B 69 , 224501 (2004). [37] Y. Zuev, M.S. Kim, and T.R. Lemberger, Phys. Rev. Lett. 95 , 137002 (2005). [38] C.P. Poole, H.A. Farach, and R.J. Creswick, Supercon- ductivity (Academic Press, London, 1995). [39] H. Krakauer, W.E. Pickett, and R.E. Cohen, J. Super- cond. 1 , 111 (1998).