| Number | Name | Date | Kind |
|---|---|---|---|
| 5874943 | Fitzpatrick et al. | Feb 1999 | A |
| 6014142 | LaHood | Jan 2000 | A |
| 6154205 | Carroll et al. | Nov 2000 | A |
| 6323878 | Haffey et al. | Nov 2001 | B1 |
| 6326970 | Mott et al. | Dec 2001 | B1 |
| 6333752 | Hasegawa et al. | Dec 2001 | B1 |
| 6339434 | West et al. | Jan 2002 | B1 |
| Entry |
|---|
| B. Bederson, J. Hollan, K. Perlin, et al., Pad++: A Zoomable Graphical Sketchpad for Exploring Alternate Interface Physics, Journal of Visual Languages and Computing, 7, 3-31, 1996. |