1. See e.g. M. Tinkham, ”Introduction to Superconductivity”, Mc Graw-Hill (1975), chap.3.
2. See e.g. P.G. De Gennes, ”Superconductivity in Metals and Alloys”, W.A. Benjamin (1966) chap.6.
3. Analytical solutions are available only in the two limiting cases, d » or d«; in the intermediate thickness region only numerical solutions have been obtained. See for example H.J. Fink, D.S. McLachlan and B. Rothberg-Bibby, in Progress of Low Temperature Physics VIlb, D.F. Brewer ed. North-Holland (1978), p.435.
4. L. Leplae, F. Mancini and H. Umezawa, Physics Report 10C, 151 (1974).
5. L. Leplae, F. Mancini and H. Umezawa, Phys.Rev. 3594 (1970), 884 (1972).