| Number | Name | Date | Kind |
|---|---|---|---|
| 2926378 | Eichhorn et al. | Mar 1960 | A |
| 3254361 | Brunn et al. | Jun 1966 | A |
| 4092450 | Haren | May 1978 | A |
| 4563378 | Roth | Jan 1986 | A |
| Number | Date | Country |
|---|---|---|
| 1 498 079 | Jan 1978 | GB |
| 2 221 838 | Feb 1990 | GB |
| 2 278 542 | Dec 1994 | GB |
| WO 9955954 | Nov 1999 | WO |
| Entry |
|---|
| Research Disclosure 430102, Feb. 2000. |