| Number | Name | Date | Kind |
|---|---|---|---|
| 2048313 | Adolfson | Jul 1936 | |
| 2306209 | Elofson et al. | Dec 1942 | |
| 3952984 | Dimitry | Apr 1976 | |
| 3990565 | Felton et al. | Nov 1976 | |
| 4085961 | Brown | Apr 1978 | |
| 4307672 | Shikimi | Dec 1981 | |
| 4437638 | Scheibenpflug | Mar 1984 |
| Entry |
|---|
| "Office Products Dealer" vol. 110, No. 6, Jun. 1982, p. 114. |