| Number | Date | Country | Kind |
|---|---|---|---|
| 197 07 687 | Feb 1997 | DEX |
| Number | Name | Date | Kind |
|---|---|---|---|
| 5256003 | Ito et al. | Oct 1993 | |
| 5647690 | Landau | Jul 1997 |
| Number | Date | Country |
|---|---|---|
| 22 60 473 | Jun 1974 | DEX |
| Entry |
|---|
| Patent Abstracts of Japan, vol. 8, No. 28 (M-278) and JP 58 185819 (Yoshinori) entitled "Crushed Stone Piling Work"; Feb. 7, 1984. |
| Holeyman, "Uitvoering van de grondverberering", Viviele Techniek, Bd. 39, Nr. 3, Mar. 1984, (Rijswijk, Netherlands). |