| Number | Name | Date | Kind |
|---|---|---|---|
| 3594727 | Braun | Jul 1971 | |
| 4020463 | Himmel | Apr 1977 | |
| 4027142 | Paup et al. | May 1977 | |
| 4048618 | Hendry | Sep 1977 |
| Entry |
|---|
| Nagel et al., "Steps Toward Handwritten Signature Verification", Proc. of 1st International Joint Conf. on Pattern Rec.: 1973, pp. 59-65. |