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| AS SØREIDE VVS | 963930194 | VOSS |
| A/S SørMek | 947038400 | LINDESNES |
| AS STAFF & SØNNER | 916176333 | ØSTRE TOTEN |
| A/STAB AS | 984548648 | BERGEN |
| ASTAD ARKITEKTUR AS | 920575307 | OSLO |
| AS TOFT MESTERRØR | 917037809 | ØYGARDEN |
| ASTRA BYGG & ENTREPRENØR AS | 978712967 | STEINKJER |
| ASTRAKOM AS | 980507653 | BÆRUM |
| A SVELA MASKIN AS | 919993626 | TIME |
| AS WATT | 958862431 | BÆRUM |
| ASW BYGG AS | 916747772 | BERGEN |
| ATAM AS | 929578171 | ASKER |
| A. TANGEN AS | 926704834 | RINGERIKE |
| AT ARKITEKTUR AS | 986676813 | TROMSØ |
| AT-BYGG AS | 920349536 | SANDEFJORD |
| AT BYGGSERVICE AS | 912737489 | KRISTIANSUND |
| AT CONSULT LARISA KARTASHEVA | 915712754 | OSLO |
| ATEAM INNEKLIMASERVICE AS | 982175577 | OSLO |
| ATE AS | 998196310 | PORSGRUNN |
| ATECCO AS | 924813423 | AURSKOG-HØLAND |
| A-TECH BYGGMONTERING AS | 930951293 | BAMBLE |
| ATEC VOSS AS | 987309547 | VOSS |
| ATELIER GRØSTAD ARKITEKTUR AS | 943885486 | NOTODDEN |
| ATELIER LORENTZEN LANGKILDE APS | 813431602 | |
| ATELIER OSLO AS | 994734938 | OSLO |
| ATH BYGGSERVICE AS | 911742063 | NORDRE FOLLO |
| A TIL Å ENTREPRENØR AS | 972416533 | TINN |
| ATLANT ENTREPRENØR AS | 918270116 | TØNSBERG |
| ATLANTERBYGG OG EIENDOM AS | 927302306 | KRISTIANSUND |
| ATLANTERPRODUKTER AS | 968651242 | VESTVÅGØY |
| ATL BYGG AS | 932695030 | TRONDHEIM |
| ATLE BEKKEVOLD | 878663292 | RINGSAKER |
| ATLE MYRENE AS | 995073560 | ULSTEIN |
| ATMOS AS | 989831208 | TRONDHEIM |
| ATOM ELEKTRO AS | 893022392 | OSLO |
| ATOM RØRLEGGERBEDRIFTS AS | 924201746 | BÆRUM |
| ATP ARKITEKTER AS | 897489422 | OSLO |
| ATRACK ENTREPRENØR AS | 983380921 | ASKER |
| ATRE AS | 827649392 | AUSTEVOLL |
| ATRE-BYGG AS | 999333370 | STJØRDAL |
| A-TRE KONSULT AS | 980333183 | TØNSBERG |
| ATRI BYGGPROSJEKTERING AS | 957563104 | SARPSBORG |
| A & T RØR AS | 998195551 | HORTEN |
| AT RØR AS | 950343656 | RANDABERG |
| ATR VVS AS | 988478288 | LILLESTRØM |
| AUDEN SENDERUD GRAVEMASKINDRIFT AS | 979940084 | ELVERUM |
| AUDNA BYGG AS | 999042589 | LINDESNES |
| AUENSEN MASKINENTREPRENØR AS | 997890930 | HALDEN |
| AUKE RØR AS | 813458942 | NITTEDAL |