| Number | Name | Date | Kind |
|---|---|---|---|
| 4191467 | Schieck | Mar 1980 | |
| 4754960 | Muller | Jul 1988 | |
| 4761663 | Piatt et al. | Aug 1988 |
| Number | Date | Country |
|---|---|---|
| 78875 | May 1984 | JPX |
| Entry |
|---|
| Ryan, R. A., et al., "Forms Stacking Aid", IBM Technical Disclosure Bulletin, vol. 20, No. 1 (Jun 1977), p. 97. |