| Number | Name | Date | Kind |
|---|---|---|---|
| 2186435 | Serr | Jan 1940 | |
| 2240522 | Serr | May 1941 | |
| 2359881 | Serr | Oct 1944 | |
| 2360597 | Topolski | Oct 1944 | |
| 2467875 | Andrews | Apr 1949 | |
| 2596620 | Townsend | May 1952 | |
| 2819738 | Marberg | Jan 1958 | |
| 2926833 | Engleson et al. | Mar 1960 | |
| 3008835 | Madding | Nov 1961 | |
| 3043424 | Howard | Jul 1962 | |
| 3797646 | Horne | Mar 1974 | |
| 3867559 | Hans | Feb 1975 | |
| 4721622 | Kingham et al. | Jan 1988 | |
| 5094863 | Vandenburg | Mar 1992 | |
| 5332586 | Dimino | Jul 1994 | |
| 5489658 | Huang | Feb 1996 | |
| 5567455 | Alsbrook, Sr. | Oct 1996 |
| Number | Date | Country |
|---|---|---|
| 2252533 | Nov 1997 | CA |
| 4117093 | Nov 1992 | DE |
| 612476 | Aug 1994 | EP |
| 2203927 | Nov 1988 | GB |
| 4-112751 | Apr 1992 | JP |
| 5-95761 | Apr 1993 | JP |
| WO9740693 | Nov 1997 | WO |
| Entry |
|---|
| Wiley Encyclopedia of Packaging Technology pp. 185, 196, (Bakker-Editor) J. Wiley & Sons, 1986. |