| Number | Name | Date | Kind |
|---|---|---|---|
| 3009129 | Kirk, Jr. | Nov 1961 | |
| 3345604 | Henschen et al. | Oct 1967 | |
| 4367967 | Albert, Jr. | Jan 1983 | |
| 4678867 | Bongard et al. | Jul 1987 | |
| 5037175 | Weber | Aug 1991 | |
| 5315062 | Hoshino | May 1994 | |
| 5421740 | Dittburner et al. | Jun 1995 | |
| 5816842 | Thantrakul et al. | Oct 1998 |
| Entry |
|---|
| IBM Technical Disclosure Bulletin, vol. 34 No. 1, pp. 150-151, Jun. 1991. |