| Number | Date | Country | Kind |
|---|---|---|---|
| 6050/74 | May 1974 | CH |
| Number | Name | Date | Kind |
|---|---|---|---|
| 2128508 | Stosser et al. | Sep 1938 | |
| 3514439 | Wehrli et al. | May 1970 | |
| 3565884 | Haag et al. | Feb 1971 | |
| 3676050 | James | Jul 1972 |
| Number | Date | Country |
|---|---|---|
| 955,085 | Apr 1964 | UK |
| Entry |
|---|
| Venkataraman, The Chemistry of Synthetic Dyes, vol. I, Academic Press Inc., New York, 1952, p. 270. |