| Number | Name | Date | Kind |
|---|---|---|---|
| 3151499 | Roe | Oct 1964 | |
| 3563111 | Zeigler | Feb 1971 | |
| 3643524 | Herring | Feb 1972 | |
| 5306136 | Oomori et al. | Apr 1994 | |
| 5329657 | Bartley et al. | Jul 1994 | |
| 5697260 | Rixon | Dec 1997 | |
| 5884532 | Rixon et al. | Mar 1999 | |
| 6019015 | Elton | Feb 2000 |
| Entry |
|---|
| IBM Technical Disclosure Bulletin vol. 10, No. 8, Jan. 1968. |