| Number | Name | Date | Kind |
|---|---|---|---|
| 4228630 | Englert et al. | Oct 1980 | |
| 4811533 | Wetsel | Mar 1989 | |
| 5014466 | Winner | May 1991 | |
| 5487243 | Hale et al. | Jan 1996 | |
| 5921037 | Minter | Jul 1999 | |
| 5983579 | Young | Nov 1999 |
| Entry |
|---|
| Hawley's Condensed Chemical Dictionary, Irving N. Sax, 1987, Van Nostrand Reinhold Company, 181-192. |