1. J. Bardeen, L.N. Cooper, J.R. Schrieffer, Phys.Rev. 106, 162 (1957); 108, 1175 (1957)
2. L.P. Gor’kov, Sov.Phys.JETP 7 505 (1958); 9, 1364 (1959); 10, 998 (1960)
3. A.A. Abrikosov, Sov.Phys.JETP 5, 1175 (1957)
4. W.H. Kleiner, L.M. Roth, S.H. Autler, Phys.Rev. 133, A1226 (1964)
5. J. Matricon, Phys.Lett. 9, 289 (1964)