1. For a review we refer to the articles and references in: Mooij, J.E., Sch�n, G.B.I. (eds.) Proceedings of the NATO advanced research workshop on Coherence in superconducting networks. Physica B152, 1 (1988)
2. De Gennes, P.G.: C.R. Acad. Sci. Ser. B292, 279 (1981)
3. Skal, A.S., Shklovskii, B.I.: Fiz. Tekh. Poluprovodn.8, 1586 (1974) [Sov. Phys. Semicond.8, 1029 (1975)]
4. De Gennes, P.G.: J. Phys. (Paris)37, L1 (1976)
5. Springer Series in Solid-State Sciences;B.I. Shklovskii,1984