| Number | Name | Date | Kind |
|---|---|---|---|
| 3767422 | Levitz | Oct 1973 | A |
| 4511585 | Durst | Apr 1985 | A |
| 4904493 | Petrizzelli | Feb 1990 | A |
| 5178893 | Seewi et al. | Jan 1993 | A |
| 5366744 | Drummond et al. | Nov 1994 | A |
| 5384139 | Vasseneix | Jan 1995 | A |
| 5624697 | Lin et al. | Apr 1997 | A |
| 6039994 | Leflecher et al. | Mar 2000 | A |
| Number | Date | Country |
|---|---|---|
| 0443219 | Aug 1991 | EP |
| 0868850 | Oct 1998 | EP |
| Entry |
|---|
| The Wiley Encyclopedia of Packaging Technology, 1986, p. 218-221. |