| Number | Date | Country | Kind |
|---|---|---|---|
| 2822632 | May 1978 | DEX |
| Number | Name | Date | Kind |
|---|---|---|---|
| 3328385 | Loeffel et al. | Jun 1967 | |
| 4131733 | Hanger | Dec 1978 |
| Number | Date | Country |
|---|---|---|
| 2093270 | Dec 1972 | FRX |
| Entry |
|---|
| ]Hackh's Chemical Dictionary, Julius Grant, pp. 50-51, McGraw-Hill Book Co., 1972. |