| Number | Date | Country | Kind |
|---|---|---|---|
| 75 02684 | Jan 1975 | FRX | |
| 75 36426 | Nov 1975 | FRX |
| Number | Name | Date | Kind |
|---|---|---|---|
| 3028385 | Batzer et al. | Apr 1962 | |
| 3247043 | Cardina | Apr 1966 | |
| 3449340 | Orth et al. | Jun 1969 |
| Number | Date | Country |
|---|---|---|
| 1,267,432 | Jun 1961 | FRX |
| 2,070,240 | Sep 1971 | FRX |
| Entry |
|---|
| Japanese Application 74/040879, 11/68. |