| Number | Date | Country | Kind |
|---|---|---|---|
| 4101822 | Jan 1991 | DEX |
| Number | Name | Date | Kind |
|---|---|---|---|
| 3700623 | Keim | Oct 1972 | |
| 3932363 | Lehmann et al. | Jan 1976 | |
| 4975499 | Bachem et al. | Dec 1990 | |
| 5082527 | Bachem et al. | Jan 1992 | |
| 5093470 | Bachem et al. | Mar 1992 |
| Number | Date | Country |
|---|---|---|
| 0335158 | Oct 1989 | EPX |
| Entry |
|---|
| Database WPIL, Section Ch, Week 8634, Dec. 27, 1984, Derwent Publications Ltd., London, GB, Class A, AN 222138 & JP-A-61 152 900 (Arakawa Kagaku Kogyo). |