| Number | Date | Country | Kind |
|---|---|---|---|
| 5-056099 | Mar 1993 | JPX | |
| 5-225949 | Sep 1993 | JPX |
| Number | Name | Date | Kind |
|---|---|---|---|
| 4827410 | Corren | May 1989 | |
| 5300943 | Jakobs et al. | Apr 1994 |
| Entry |
|---|
| "A Digital Desk Calculator: Tangible Manipulation on a Desk Top Display", pp. 27-33, UIPT'91, Nov. 11-13, 1991, P. Wellner. |