| Number | Name | Date | Kind |
|---|---|---|---|
| 3898437 | Butler | Aug 1975 | |
| 4192510 | Miller | Mar 1980 | |
| 4266214 | Peters | May 1981 | |
| 4268744 | McGeary | May 1981 | |
| 4367526 | McGeary et al. | Jan 1983 | |
| 4419655 | May | Dec 1983 | |
| 4480310 | Alvarez | Oct 1984 | |
| 4783800 | Levine | Nov 1988 | |
| 4910677 | Remedio et al. | Mar 1990 |
| Entry |
|---|
| "Voice Response System and Its Applications", Y. Ozawa et al., Hitachi Review, vol. 28 (1979), No. 6, pp. 301-305. |