U.S. Patent No.
5305017; 5349303; 5565658; 5757368; 5767457; 5861875; 5914708; 6222528; 6262717; 6473069; 6639586; 6680731; 6730863;

Japan Patent No.
3181581; 3833709;

EP(UK) Patent No.
0486617; 0814423; 0706715;

France Patent No.
0486617; 0814423; 0706715;

Germany Patent No.
690 32 101.5-08; 690 33 769.8-08; 694 31 721.7;

China Patent No.
94192926.4; 95197542.0; 99808153.1;

Republic of Korea Patent No.
0298702;