Permanent establishment taxation: profits attributable to the local establishment may be taxed where business is carried on there. Profits of an enterprise are taxable 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, related sales of similar goods, or other similar activities may be taxed there; such profits are attributed on the separate enterprise basis, may be reasonably estimated if necessary, allow deductions for expenses incurred for the permanent establishment subject to local taxation law limitations, exclude non-reimbursed head-office charges and, except for banks, interest between head office and permanent establishment, and must be determined by a consistent method year by year unless justified otherwise.