| Number | Date | Country | Kind | 
|---|---|---|---|
| 63-179146 | Jul 1988 | JPX | |
| 63-239863 | Sep 1988 | JPX | |
| 1-100132 | Apr 1989 | JPX | |
| 1-100133 | Apr 1989 | JPX | 
| Number | Name | Date | Kind | 
|---|---|---|---|
| 3169121 | Goldberg | Feb 1965 | |
| 3553167 | Schnell et al. | Jan 1971 | |
| 4579934 | Brinkmeyer et al. | Apr 1986 | 
| Number | Date | Country | 
|---|---|---|
| 60-38427 | Feb 1985 | JPX | 
| 62-70417 | Mar 1987 | JPX | 
| 1568541 | May 1980 | GBX | 
| Entry | 
|---|
| EP-A-303,931 (Abstract) 2.89. | 
| EP-A-303,935 (Abstract) 2.89. |