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| Siciarek Jaroslaw | Pl - 62 862 Iwanowice | 2015 |
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| Siemens Energy SAS | Fr-93527 Saint-Denis | 2023 |
| Siemens Gamesa Renewable Energy GmbH & Co. KG | De-20097 Hamburg | 2017 |
| Siemens Industrial Turbomachinery Ltd | Dyce Ab21 0Bg Aberdeen Scotland | 2005 |
| Siemens Nederland N.V. | 2595Bn Den Haag | 2003 |
| Siemens S.R.O. | Cz-15500 Praha | 2006 |
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| Sigdal Anleggsservice AS | Solumsmoen | 2018 |
| Sigdal Blikk & Tak AS | Åmot | 2011 |
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| Sigdal Heating Solutions AS | Nedre Eggedal | 2023 |
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| Sigdal Tipptransport AS | Prestfoss | 2026 |
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| Sik Service AS | Nodeland | 2026 |
| Sikker Jernbane AS | Oslo | 2015 |
| Sikker Service AS | Finstadjordet | 2015 |
| Sikker Utførelse AS | Straumsgrend | 2024 |
| Sikker VVS AS | Oslo | 2026 |
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| Sikkerhet Experten Midt-Norge AS | Trondheim | 2025 |
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| SIKRING24 AS | Nesoddtangen | 2026 |
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| Silikal Nordvest AS | Sistranda | 2014 |
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