1. J. Bardeen, L. N. Copper, J. R. Schrieffer: Phys. Rev. 108, 1175 (1957)
2. See, e.g., M. Tinkham: Introduction to Superconductivity, McGraw-Hill, New York (1975)
3. See review: C. C. Tsuei, J. R. Kirtley: Rev. Mod. Phys. 72, 969 (2000)
4. See, e.g., A. A. Abrikosov: cond-mat/9912394 (1999)
5. See also e.g., J. Bouvier, J. Bok: Physica C217-225, 217 (1997);