| Number | Name | Date | Kind |
|---|---|---|---|
| 3489342 | Anderson | May 1968 | |
| 3982081 | Demler, Jr. | Sep 1976 | |
| 4363942 | Deeg et al. | Dec 1982 | |
| 5172990 | Weng | Dec 1992 |
| Entry |
|---|
| "Reduced Noise Keybutton", IBM Technical Disclosure, vol. 31 No. 11 Apr. 1989, pp. 43-44. |
| "Changeable Key Pad Overlay and Key Pad Panel", IBM Technical Disl. Bulletin vol. 29, No. 5, Oct. 1986, pp. 2199-2000. |
| Cooper et al., "Changeable Array Keyboard", IBM Technical Disclosure Bulletin vol. 11, No. 5, Oct. 1968, p. 524. |
| "Low Cost Versatile Control Panel", vol. 28, No. 7, Dec. 1985, pp. 2948-2949 IBM Technical Disclosure Bulletin. |