| Number | Name | Date | Kind |
|---|---|---|---|
| 2819079 | Beaulieu | Jan 1958 | |
| 3095192 | Simjian | Jun 1963 | |
| 4047712 | Burkhardt et al. | Sep 1977 | |
| 4273325 | Rodewald | Jun 1981 | |
| 4705157 | Bowles | Nov 1987 | |
| 5109987 | Daboub et al. | May 1992 |
| Entry |
|---|
| IBM Technical Disclosure Bulletin, Karanza, Document Twisting Transport, vol. 22, No. 10, Mar. 1980, 4619-4620. |