| Number | Date | Country | Kind |
|---|---|---|---|
| 2774/80 | Nov 1980 | HUX |
| Number | Name | Date | Kind |
|---|---|---|---|
| 4244888 | Budai et al. | Jan 1981 |
| Entry |
|---|
| Beilsteins Handbuch der Organischen Chemie, 4th Ed. vol. 7 (1925) pp. 112-114, Julius Springer, Publ. |
| Hackh's Chemical Dictionary, 4th Ed. (1969) at p. 127. |