| Number | Date | Country | Kind |
|---|---|---|---|
| 3331288 | Aug 1983 | DEX |
| Number | Name | Date | Kind |
|---|---|---|---|
| 3179674 | Laskin et al. | Apr 1965 | |
| 3243355 | Holmlund et al. | Mar 1966 | |
| 3766224 | Coombs | Oct 1973 |
| Number | Date | Country |
|---|---|---|
| 1223372 | Aug 1966 | DEX |
| Entry |
|---|
| CA: vol. 96 (5) Par. 35638y, Abstract of Ger. (East) DD 147. 946-Pat. Apr. 29, 1981, Kasch et al. |