| Number | Date | Country | Kind |
|---|---|---|---|
| 43 28 815.4 | Aug 1993 | DEX |
| Number | Name | Date | Kind |
|---|---|---|---|
| 1458166 | Cox | Jun 1923 | |
| 1985615 | Mitchell | Dec 1934 | |
| 2562580 | Satz et al. | Jul 1951 | |
| 4464552 | Pawlowski | Aug 1984 | |
| 4681218 | Williams | Jul 1987 | |
| 4834234 | Sacherer et al. | May 1989 | |
| 4865988 | Guala | Sep 1989 |
| Number | Date | Country |
|---|---|---|
| 3519296A1 | Jan 1986 | DEX |
| 2263273 | Jul 1983 | GBX |
| Entry |
|---|
| Database WPI, Section Ch, Week 8711, Derwent Publications Ltd. London, GB. |