| Number | Name | Date | Kind |
|---|---|---|---|
| 5465084 | Cottrell | Nov 1995 | |
| 5559961 | Blonder | Sep 1996 | |
| 5608387 | Davies | Mar 1997 | |
| 5821933 | Keller et al. | Oct 1998 |
| Number | Date | Country |
|---|---|---|
| 0 677 801 A1 | Oct 1995 | EP |
| 60-171560 | Sep 1985 | JP |
| 61-142835 | Jun 1986 | JP |
| 9-128208A | May 1997 | JP |
| Entry |
|---|
| Knowledge Adventure, Inc., JumpStart Toddlers User's Guide, Knowledge Adventure, Inc., 1996, pp. 1-18. |