| Number | Name | Date | Kind |
|---|---|---|---|
| 3236352 | Schacht | Feb 1966 | |
| 3712443 | Mathews | Jan 1973 | |
| 3823389 | Heitman et al. | Jul 1974 | |
| 3834507 | Bradshaw | Sep 1974 | |
| 3912064 | Bluem et al. | Oct 1975 | |
| 3913721 | Koplow et al. | Oct 1975 | |
| 3981383 | Bittner et al. | Sep 1976 | |
| 4015700 | Paque | Apr 1977 | |
| 4050565 | Heider et al. | Oct 1977 | |
| 4108556 | Connoy | Aug 1978 | |
| 4225249 | Kettler et al. | Oct 1980 | |
| 4243333 | Bradshaw et al. | Jan 1981 |
| Number | Date | Country |
|---|---|---|
| 0024620 | Mar 1981 | EPX |
| 2922006 | Dec 1979 | DEX |
| Entry |
|---|
| IBM Technical Disclosure Bulletin, vol. 19, No. 12, 5-'77, pp. 4691-4692, Written by S. F. Kambic. |