| Number | Name | Date | Kind |
|---|---|---|---|
| 1596661 | Hutchings | Aug 1926 | |
| 2122956 | Salley | Jul 1938 | |
| 2177071 | Klein et al. | Oct 1939 | |
| 2755576 | Golden | Jul 1956 | |
| 2871153 | Copen | Jan 1959 | |
| 2888932 | Freiberg | Jun 1959 | |
| 3292632 | Hopen | Dec 1966 | |
| 3555713 | Leinbach | Jan 1971 | |
| 3816948 | Mooney et al. | Jun 1974 | |
| 4365433 | Buell | Dec 1982 | |
| 4560068 | Membrino | Dec 1985 | |
| 4614450 | Neiman | Sep 1986 | |
| 4704042 | Eisen et al. | Nov 1987 | |
| 4848576 | Stemmer, Jr. | Jul 1989 | |
| 5096752 | Wagner | Mar 1992 |
| Number | Date | Country |
|---|---|---|
| 977148 | Mar 1951 | FRX |
| 1436813 | Jan 1969 | DEX |
| Entry |
|---|
| The 1988 Jacobs Gardner Office Products Catalog, pp. 244-245. |
| The 1989 Miller's Office Products Catalog, pp. 254-255. |