| Number | Date | Country | Kind |
|---|---|---|---|
| 9204128 | Feb 1992 | GBX |
| Filing Document | Filing Date | Country | Kind | 102e Date | 371c Date |
|---|---|---|---|---|---|
| PCT/GB93/00397 | 2/26/1993 | 8/28/1995 | 8/28/1995 |
| Publishing Document | Publishing Date | Country | Kind |
|---|---|---|---|
| WO93/17764 | 9/16/1993 |
| Number | Name | Date | Kind |
|---|---|---|---|
| 4372558 | Shimamoto et al. | Feb 1983 | |
| 4848767 | Correro | Jul 1989 | |
| 4884974 | DeSmet | Dec 1989 | |
| 4990092 | Cummings | Feb 1991 | |
| 5011156 | LaChance, Jr. et al. | Apr 1991 |
| Number | Date | Country |
|---|---|---|
| 2112990 | Jul 1983 | GBX |
| Entry |
|---|
| Texas Instruments' 1990 Educational Products brochure, p. 13. |