| Number | Name | Date | Kind |
|---|---|---|---|
| 2100372 | Barton | Nov 1937 | |
| 2585780 | Johnson | Feb 1952 | |
| 3517933 | Malkin | Jun 1970 | |
| 3757460 | Morrison | Sep 1973 | |
| 3828462 | Morrison et al. | Aug 1974 | |
| 3877697 | Lersch | Apr 1975 |
| Number | Date | Country |
|---|---|---|
| 411669 | Apr 1925 | DE2 |
| Entry |
|---|
| "Paperweight-Timer", Brookstone Co. Catalog, Fall 1976, p. 27. |