1. V.K. Mathur, International Patent Application WO 01/14274 A1, March 1, 2001
2. T. Kazuto, K. Kiyoshi, N. Yasunori, O. Yasuhiro, U.S. Patent 6 190 633, February 20, 2001
3. J. Arika, M. Takitani, K. Mitarai, K. Yamamoto, U.S. Patent 4 157 379, June 5, 1979
4. Y. Ota, N. Goto, I. Motoyama, T. Iwashita, K. Nomura, U.S. Patent 4 824 654, April 25, 1989
5. G.H. Fairchild, R.L. Thatcher, U.S. Patent 6 071 336, June 6, 2000