| Number | Date | Country | Kind |
|---|---|---|---|
| 3513003 | Apr 1985 | DEX |
| Number | Name | Date | Kind |
|---|---|---|---|
| 2718972 | Temple | Sep 1955 | |
| 2755950 | Forshey | Jul 1956 | |
| 3499554 | Davis et al. | Mar 1970 | |
| 3526330 | Armington et al. | Sep 1970 | |
| 3695539 | Lindstaedt | Oct 1972 | |
| 3863778 | Martin, Sr. | Feb 1975 | |
| 4131206 | Kawada et al. | Dec 1978 | |
| 4331230 | Buckley | May 1982 | |
| 4406570 | Duncan et al. | Sep 1983 | |
| 4555215 | Raasch et al. | Nov 1985 |
| Number | Date | Country |
|---|---|---|
| 2124159 | Feb 1984 | GBX |
| Entry |
|---|
| IBM Technical Disclosure Bulletin--vol. 22, No. 4--Sep. 1979, p. 1364. |