1. A. S. Petrov, E. P. Naigen, V. T. Podlesnykh, et al., Superconductivity [in Russian], FKhT,6, No. 2, 373 (1993).
2. H. Piel, et al., Physica C,153–155, 1604 (1988).
3. S. Kohjiro, T. Kachino, et al., Jpn. J. Phys.,30, 1471 (1991).
4. A. S. Petrov and E. E. Slyadnikov, Superconductivity: FKhT,6, No. 3, 538 (1993).
5. A. S. Petrov, S. P. Kulaev, E. P. Naiden, et al., Int. Conf. Magnetic Electronics: Abstracts, Krasnoyarsk (1992), p. 11.