| Number | Name | Date | Kind |
|---|---|---|---|
| 4614144 | Sagara et al. | Sep 1986 | |
| 5504836 | Loudermilk | Apr 1996 | |
| 5546466 | Ishiguro et al. | Aug 1996 | |
| 5625608 | Grewe et al. | Apr 1997 |
| Entry |
|---|
| "Digital Sound Soother XS," Instruction Manual, author and date presently unknown. |
| "Marsona.RTM. 1250 Sound Conditioner," Instruction Manual, author and date presently unknown. |
| "Marsona.RTM. 1280 Sound Conditioner," Instruction Manual, author and date presently unknown. |
| "Bookman.RTM. Electronic Books," Products' Advertisement Sheet, author and date presently unknown. |