Business profits taxable in resident State unless attributable to a permanent establishment in another State. Profits are taxable only in the State of residence unless business is carried on in the other Contracting State through a permanent establishment, in which case only profits attributable to that permanent establishment and related sales or similar activities may be taxed there. Attribution follows the separate-enterprise standard, with reasonable estimation permitted where precise allocation is impracticable. Deductible expenses incurred for the permanent establishment's business are allowed, including executive and general administrative expenses incurred locally or elsewhere. No profits are attributed solely for purchases made for export to the head office. The attribution method should be applied consistently year to year, and income governed by other Articles is unaffected by this Article.