 
                 Patent Grant
 Patent Grant
                     4143228
 4143228
                    | Number | Date | Country | Kind | 
|---|---|---|---|
| 2638232 | Aug 1976 | DEX | 
| Number | Name | Date | Kind | 
|---|---|---|---|
| 2974141 | Plue | Mar 1961 | |
| 3073820 | Plue | Jan 1963 | |
| 3770727 | Brack | Nov 1973 | 
| Number | Date | Country | 
|---|---|---|
| 2,036,505 | Jan 1972 | DEX | 
| Entry | 
|---|
| Piozzo et al., Chem. Absts. 1967, vol. 67, No. 64295r. | 
| Tsukerman et al., Chem. Absts. 1969, vol. 71, No. 22060r. | 
| Gorbunova et al., Chem. Absts. 1971, vol. 74, No. 53631r. | 
| Zhungietu et al., Chem. Absts. 1973, vol. 78, No. 111271u. |