1. N. Yoshida, M. Kubota, S. Takano, M. Nagata, T. Hara, H. Ishii, T. Yamamoto and K. Maekawa: in Proc. International Conference on Advanced Materials, Strasbourg, (1991) p 561
2. N. Yoshida, K. Fujino, M.J. Cubota, S. Takano, M. Nagata, T. Hara, Hishii, T. Yamamoto and K. Maekawa: in Proc. the 4th International Symposium on Superconductivity (ISS’91), Tokyo, (1991)p529.
3. K. Fujino, N. Yoshida, S. Takano, S. Okuda, T. Hara, Hishii and T. Yamamoto: in Proc. the 5th International Symposium on Superconductivity(ISS’92), Kobe, (1992) p 615.
4. E. Narumi, L. W. Song, F. Yang, S. Patel, Y.H. Kao and D. T. Shaw: Appl. Phys. Lett, 58, (1990) p l202.
5. R.P. Reade, X.L. Mao and R.E. Russo: AppL Phys,. Lett, 59, (1991) p739.