| Number | Date | Country | Kind |
|---|---|---|---|
| 2-87660 | Apr 1990 | JPX |
| Number | Name | Date | Kind |
|---|---|---|---|
| 3800071 | Reeber | Mar 1974 | |
| 3828319 | Owen et al. | Aug 1974 | |
| 4825296 | Wagensonner et al. | Apr 1989 | |
| 4951160 | Nagahara et al. | Aug 1990 |
| Number | Date | Country |
|---|---|---|
| 0294622 | Dec 1988 | EPX |
| 2109192 | May 1983 | GBX |
| 2148655 | May 1985 | GBX |
| Entry |
|---|
| Patent Abstracts of Japan, vol. 11, No. 72, Mar. 1987. |
| European Search Report. |