| Number | Name | Date | Kind |
|---|---|---|---|
| 3253874 | Czech | May 1966 | |
| 3347609 | Mann | Oct 1967 | |
| 3763400 | Layton et al. | Oct 1973 | |
| 3936107 | Gourdeau et al. | Feb 1976 | |
| 3954244 | Gopstein | May 1976 | |
| 4003613 | Oakley | Jan 1977 | |
| 4113331 | Derdzinski et al. | Sep 1978 | |
| 4288133 | Deatherage | Sep 1981 | |
| 4736924 | Bednar | Apr 1988 |
| Number | Date | Country |
|---|---|---|
| 2744923 | Apr 1979 | DEX |
| Entry |
|---|
| Bondour et al., IBM Technical Disclosure Bulletin, Interchangable Keyboard Character Indicator, vol. 14 No. 7, 12/1971. |