| Number | Date | Country | Kind |
|---|---|---|---|
| 298 08 023 U | May 1998 | DE |
| Number | Name | Date | Kind |
|---|---|---|---|
| 2354634 | Griswold | Jul 1944 | A |
| 3230589 | McIlvaine | Jan 1966 | A |
| 4223996 | Mathis et al. | Sep 1980 | A |
| 4431310 | Ito et al. | Feb 1984 | A |
| 4654802 | Davis | Mar 1987 | A |
| 5470147 | Duckworth | Nov 1995 | A |
| 5624183 | Schuff | Apr 1997 | A |
| 5713663 | Zandberg et al. | Feb 1998 | A |
| Number | Date | Country |
|---|---|---|
| 2 323 196 | Nov 1974 | DE |
| 29 47 913 | Jun 1981 | DE |
| 30 41 107 | May 1982 | DE |
| 31 04 751 | Aug 1982 | DE |
| 36 30 301 | Mar 1988 | DE |
| 88 10 499.0 | Nov 1988 | DE |
| 38 09 661 | Oct 1989 | DE |
| 93 19 066 | Feb 1994 | DE |
| 43 35 331 | Apr 1995 | DE |
| 44 08 659 | Sep 1995 | DE |
| 197 23 474 | Dec 1998 | DE |
| 239 685 | Oct 1987 | EP |
| 530 510 | Mar 1993 | EP |
| 2 503 618 | Oct 1982 | FR |
| Entry |
|---|
| Palotas-Balazs: Beton-habares-keramia-muanyag, Akademiai Kiado, Budapest, 1980, Különösen 23, es 407-408, oldalak. |