| Number | Name | Date | Kind |
|---|---|---|---|
| 4008941 | Smith | Feb 1977 | |
| 4668036 | Ota et al. | May 1987 | |
| 4893263 | Myers | Jan 1990 | |
| 4960384 | Singer et al. | Oct 1990 | |
| 4979909 | Andrews | Dec 1990 | |
| 5103378 | Stowers et al. | Apr 1992 |
| Entry |
|---|
| IMB Technical Disclosure Bulletin, vol. 19, No. 11, Apr. 1977. |
| IBM Technical Disclosure Bulletin, vol. 33, No. 4, Sep. 1990. |