| Number | Name | Date | Kind |
|---|---|---|---|
| 3537393 | Hegi | Jan 1970 | |
| 3651503 | Kono | Mar 1972 | |
| 3731622 | Baranoff | May 1973 | |
| 3734011 | Williams | May 1973 | |
| 3899971 | Dudley | Aug 1975 | |
| 3921516 | Toft et al. | Nov 1975 | |
| 3951061 | Bremoer et al. | Apr 1976 |
| Entry |
|---|
| Malinacki, IBM Technical Disclosure Bulletin, vol. 11, No. 2, July 1968, p. 186. |