| Number | Name | Date | Kind |
|---|---|---|---|
| 3394231 | Hopper et al. | Jul 1968 | |
| 4191860 | Weber | Mar 1980 | |
| 4707853 | Hasegawa | Nov 1987 | |
| 4862390 | Weiner | Aug 1989 | |
| 5136690 | Becker et al. | Aug 1992 |
| Entry |
|---|
| Electrical Communication, vol. 63, No. 3, 1989, "Computer Assisted Network Engineering", C. Guthmann, pp. 279-285. |