1. Current works of active groups in this field can be found in the special issue ofNucl. lustrum. Methods A,370 (1996).
2. Barone A., De Stefano S., Darbo G., Gallinaro G., Siri S., Vitale S. andVaglio R., inProc. of LT 17 Part II, edited byU. Eckern, A. Schmid, W. Weber andH. Wuhl (North-Holland, Amsterdam) 1984, pp. 933–934.
3. Houwman E. P., Gijsbertsen J. G., Flokstra J. andRogalla H.,Physica C,183 (1991) 339.
4. Gaidis M. C., Friedrich S., Prober D. E., Szymkowiak A. E. andMoseley S. H.,IEEE Trans. Supercond.,3 (1993) 2088;J. Low Temp. Phys.,93 (1993) 605.
5. Gijsbertsen J. G., Houwman E. P., Flokstra J., Rogalla H.,Physica B,194-196 (1994) 1705.