| Number | Date | Country | Kind |
|---|---|---|---|
| DM/032 626 | Mar 1995 | WOX |
| Number | Name | Date | Kind |
|---|---|---|---|
| 3050874 | Silombra | Aug 1962 | |
| 3354562 | Munari | Nov 1967 | |
| 3363342 | Stohr | Jan 1968 | |
| 3535799 | Onitsuka | Oct 1970 | |
| 4227322 | Annoui | Oct 1980 | |
| 4441265 | Burns et al. | Oct 1984 | |
| 4571856 | Lin et al. | Feb 1986 | |
| 4937952 | Oliveri | Jul 1990 | |
| 5499461 | Danezin et al. | Mar 1996 |