| Number | Name | Date | Kind |
|---|---|---|---|
| 3416701 | Kramer et al. | Dec 1968 | |
| 4157763 | Bethejewski et al. | Jun 1979 | |
| 4279357 | Robinson | Jul 1981 |
| Entry |
|---|
| "The Unbreakables", pp. 6-8, Tucker Housewares Catalog, 345 Control St., Leominister, MA 01453, Publ. 1985. |
| Catalog, p. 21, Rubbermaid Canada Inc., 2562 Stanfield Road, Mississauga, Ontario L4Y1S5, Publ. 1986. |