ifc

http://ifcowl.openbimstandards.org/IFC2X3_Final# link to namespace URI +1+1

https://standards.buildingsmart.org/IFC/DEV/IFC4/ADD2_TC1/OWL# link to namespace URI +1+1

http://www.buildingsmart-tech.org/ifcOWL/IFC4_ADD1# link to namespace URI +1+1

Add alternative URI
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