1. R. Lisowsky, US Patent 5,708,150 (1998), based on Eur. Pat. Appl. 718,303 (1996).
2. J.Y. Lee, E.A. Burt, US Patent 5,569,746 (1996).
3. J.Y. Lee, M.-S. Ao, S.E. Belmont, L.H. Shepherd, Jr., US Patent 5,648,583 (1997), based on Eur. Pat. Appl. 739,872 (1996).
4. W.J. Layman, G.C. Robinson, US Patent 5,648,578 (1997), based on Eur. Pat. Appl. 739,874 (1996).
5. Y. Matsumura, K. Suyama, Y. Inomata, Eur. Pat. Appl. 705,812 (1996).