1. Barber Nichols Inc., http://www.barber-nichols.com/products/pumps/cryogenic-pumps/liquid-nitrogen-pumps.
2. Fujihira Co., Ltd., URL: http://www.fujihira-gr.co.jp/English/Index%20eng.html.
3. Kakihara, K., Okada, Y., and Koyanagi, H., Development of IPM type Hybrid Magnetic Bearing, Proc. of 6th Korea-Japan Symposium of Frontiers in Vibration Science and Technology, (2005), pp. 32-35, Hitachi JAPAN.
4. Kakihara, K., Otsuka, Y., Kurita, N., and Okada, Y., Development of Wide-Gap Hybrid Magnetic Bearing, CD-ROM Proc. of 8th Int. Conf. on Motion and Vibration Control, (2006), pp. 1-6, KAIST, Daejeon, Korea.
5. Kodama, S., et. al., Development of 5 DOF IPM Type Magnetic Bearing, CD-ROM Proc. of 8th Int. Conf. on Motion and Vibration Control, (2006), pp. 1-6, KAIST, Daejeon, Korea.