| Number | Date | Country | Kind |
|---|---|---|---|
| 4117902.1 | May 1991 | DEX |
| Number | Name | Date | Kind |
|---|---|---|---|
| 3807952 | Lauchenauer | Apr 1974 |
| Number | Date | Country |
|---|---|---|
| 0359039 | Mar 1990 | EPX |
| 3831093 | Mar 1990 | DEX |
| 53-23893 | Mar 1978 | JPX |
| Entry |
|---|
| World patents Index, File Supplier, Derwent Publications, Ltd., AN 75-38193W, & JP-A-49 093 700, Sep. 5, 1974. |