| Number | Name | Date | Kind |
|---|---|---|---|
| D362752 | Steurer | Oct 1995 | |
| 2633573 | Sanders | Apr 1953 | |
| 3799413 | McBain | Mar 1974 | |
| 4401246 | Dickinson et al. | Aug 1983 | |
| 5042704 | Izzo | Aug 1991 | |
| 5267608 | Torok | Dec 1993 | |
| 5318209 | Rader et al. | Jun 1994 |
| Number | Date | Country |
|---|---|---|
| 86924 | Feb 1956 | NOX |
| Entry |
|---|
| "BackSaver" advertisement, Smithsonian Magazine, Jul. 1997. |