| Number | Name | Date | Kind |
|---|---|---|---|
| 3103732 | Woodell | Sep 1963 | |
| 4392916 | Nishiyama et al. | Jul 1983 |
| Number | Date | Country |
|---|---|---|
| 62-62827 | Mar 1987 | JPX |
| 62-100534 | May 1987 | JPX |
| 241473 | Feb 1990 | JPX |
| 2160972 | Jun 1990 | JPX |
| Entry |
|---|
| "Kobunshikako"-Kobunshi Kankokai, vol. 14, pp. 198-205 (1965). |
| "Kobunshi Kagaku"-Kobunshi Gakkai, vol. 30, pp. 320-326 (1973). |