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| US6811350 | 7 oct. 2003 | 2 nov. 2004 | | Method and apparatus for adjusting the height and inclination of roadway and greenway appurtenances |
| US6997639 | 27 oct. 2004 | 14 févr. 2006 | | Method and apparatus for adjusting the height and inclination of roadway and greenway appurtenances |
