1. C. Benvenuti, D. Bloess, E. Chiaveri, N. Milleret, M. Minestrini, and W. Weingarten, in ?Proceedings of the European Particle Accelerator Conference,? Rome (1988).
2. R. Di Leo, G. Nobile, V. Palmieri, R. Vaglio, F. C. Matacotta, G. Turisini, and E. Olzi, in ?Weak superconductors,? A. Barone and A. Larking, eds. (Word Scientific, Singapore, (1987).
3. K. Agyeman, I. M. Puffer, J. A. Yasaitis, and R. M. Rose,IEEE Trans. Magn. MAG-13, 343 (1977).
4. J. Talvacchio, M. A. Janocko, and J. Greggi,J. Low Temp. Phys. 64, 395 (1986).
5. J. R. Gavaler, M. A. Janocko, and C. K. Jones, in ?Low-Temperature Physics?LT13,? K. D. Timmerhaus, W. J. O'Sullivan, and E. F. Hammel, eds. (Plenum Press, New York, 1972), Vol. 3, p. 558.