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| WILSKOG BYGG AS | 989921320 | NITTEDAL |
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| WINCON AS | 922687048 | LILLESAND |
| WINGE GRAVESERVICE AS | 920038964 | VÅLER (ØSTFOLD) |
| WINGEREID MASKIN AS | 923110186 | DRANGEDAL |
| WINGES SERVICE AS | 998100178 | FROSTA |
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| WISLAN RØR AS | 999104355 | NORDRE FOLLO |
| WITSØ MASKIN AS | 979952228 | HEIM |
| WK ENTREPRENØR AS | 980535053 | TØNSBERG |
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| WOLDEN MASKIN AS | 989077279 | BODØ |
| WOLLVIK AS | 921792697 | EIDSVOLL |
| WOOD ARKITEKTUR + DESIGN AS | 996454819 | OSLO |
| WOODSTOCK NATURLIGE BYGG AS | 826644222 | FROGN |
| WOODSTYLE AS | 925877115 | FROGN |
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| WORKMAN AS | 997306503 | OSLO |
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| WSP NORGE AS | 881894742 | OSLO |
| WWRØRLEGGER AS | 834137852 | ULLENSAKER |
| WWW.KONSTRUKSJON.COM TØRSET | 987032758 | SKAUN |
| WYX AS | 923809503 | MOSS |
| X5 ELEKTRO AS | 979705883 | ALTA |
| X BETONG AS | 912156494 | ÅLESUND |
| XBO EIENDOMSUTVIKLING AS | 927716232 | STAVANGER |
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| XFORM AS | 992186909 | SUNNFJORD |
| XK ENTREPRENØR AS | 995109409 | OSLO |
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| XPERT INSTALLASJON AS | 981574036 | TØNSBERG |
| XPLAN AS | 934995260 | FJORD |
| XYLEM WATER SOLUTIONS NORGE AS | 918088067 | LILLESTRØM |
| YC AMUNDRUD AS | 925552550 | ELVERUM |
| YJ BYGG AS | 930871575 | ASKØY |
| YM CONSULT AS | 823242832 | OSLO |
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| YRAN & DAHLE ARKITEKTER AS | 926515608 | OSLO |
| YR ARKITEKTER AS | 818946422 | BERGEN |
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| YSSEN AS | 898803902 | LILLESTRØM |