| Number | Date | Country | Kind |
|---|---|---|---|
| 2730174 | Jul 1977 | DEX |
| Number | Name | Date | Kind |
|---|---|---|---|
| 3719687 | Mendel et al. | Mar 1973 | |
| 3840598 | Lesher | Oct 1974 | |
| 4021481 | Almer et al. | May 1977 | |
| 4059621 | Vincent et al. | Nov 1977 | |
| 4070485 | Malen et al. | Jan 1978 | |
| 4146637 | Metz et al. | Mar 1979 |
| Entry |
|---|
| Metz, et al., "Chemical Abstracts", vol. 88, 1978, col. 89399z. |