| Number | Date | Country | Kind |
|---|---|---|---|
| 1-284174 | Oct 1989 | JPX |
| Number | Name | Date | Kind |
|---|---|---|---|
| 4339657 | Larson et al. | Jul 1982 | |
| 4446525 | Hoch et al. | May 1984 | |
| 4827520 | Zeinstra | May 1989 | |
| 4964077 | Eisen et al. | Oct 1990 | |
| 5115501 | Kerr | May 1992 | |
| 5159558 | Seki et al. | Oct 1992 |
| Number | Date | Country |
|---|---|---|
| 62-57063 | Mar 1987 | JPX |
| Entry |
|---|
| "APS Text Search & Retrieval Classroom Manual", Planning Research Corp., May 1987. |