| Number | Name | Date | Kind |
|---|---|---|---|
| 3795281 | Cloran | Mar 1974 | |
| 4486630 | Fetchko | Dec 1984 | |
| 4562432 | Sremac | Dec 1985 | |
| 4828418 | Sauer et al. | May 1989 | |
| 4993308 | Villeneuve | Feb 1991 |
| Entry |
|---|
| IBM Technical Disclosure Bulletin vol. 32 No. 9B Feb. 1990, (all pages). |
| IBM Technical Disclosure Bulletin vol. 33 No. 12 May 1991 (all pages). |