| Number | Name | Date | Kind |
|---|---|---|---|
| 4797339 | Maruyama et al. | Jan 1989 | |
| 4876313 | Lorah | Oct 1989 | |
| 4983488 | Tan et al. | Jan 1991 | |
| 4996127 | Hasegawa et al. | Feb 1991 | |
| 5037716 | Moffat | Aug 1991 | |
| 5139915 | Moffat et al. | Aug 1992 |
| Entry |
|---|
| Ricoh RTU Spring '92, Nippon Carbide '127 Associated Particles. |