共 44 条
[31]
1986, Patent No. 3522602
[32]
1984, Patent No. 3321738
[33]
1984, Patent No. 3310876
[34]
1987, Patent No. 3545004
[35]
1983, Patent No. 73007
[36]
1985, Patent No. 3400991
[37]
1985, Patent No. 3434059
[38]
1987, Patent No. 3621349
[39]
1976, Patent No. 2519790
[40]
1981, Patent No. 3016765