1. 1) Y. Muto, Y. Nakagawa, K. Noto, A. Hoshi, N. Miura, K. Watanabe and G. Kido: “Hybrid magnet at Tohoku University,” TEION KOGAKU 19 (1984) 394-407 (in Japanese)
2. 2) K. Noto, K. Watanabe, N. Kobayashi, A. Hoshi, S. Miura, G. Kido, Y. Nakagawa and Y. Muto: “31.1 T-hybrid magnet and superconducting materials researches held at HFLSM, Tohoku University,” Adv. Cryo. Eng. 34 (1988) 925-932
3. 3) K. Watanabe, Y. Yamada, J. Sakuraba, F. Hata, C. K. Chong, T. Hasebe and M. Ishihara: “(Nb, Ti)3Sn superconducting magnet operated at 11 K in vacuum using high-Tc (Bi, Pb)2Sr2Ca2Cu3O10 current leads,” Jpn. J. Appl. Phys. 32 (1993) L488-L490
4. 4) K. Watanabe, G. Nishijima, S. Awaji, K. Takahashi, K. Koyama, N. Kobayashi, M. Ishizuka, T. Itou, T. Tsurudome and J. Sakuraba:“Performance of a cryogen-free 30 T-class hybrid magnet,” IEEE Trans. Appl. Supercond. 16 (2006) 934-939
5. 5) K. Watanabe, S. Awaji, H. Oguro, Y. Tsuchiya, S. Hanai, H. Miyazaki, T. Tosaka, M. Takahashi and S. Ioka: “Construction of a 25-T cryogen-free superconducting magnet,” J. Phys. Conf. Series 568 (2014) 032019 (5pp)