| Number | Date | Country | Kind |
|---|---|---|---|
| 8821257 | Sep 1988 | GBX | |
| 8829265 | Dec 1988 | GBX |
| Number | Name | Date | Kind |
|---|---|---|---|
| 3651083 | Hester | Mar 1972 | |
| 3794646 | Welstead | Feb 1974 | |
| 4929614 | Calvet | May 1990 |
| Number | Date | Country |
|---|---|---|
| 0340064 | Nov 1984 | EPX |
| 0167919 | Jan 1986 | EPX |
| Entry |
|---|
| March, Advanced Organic Chemistry, pp. 370-371, (1985). |