useful starting point for the interpretation of Article XIV of the Convention is the comparable Article 14 of the 1977 OECD Model Convention. For present purposes, the slight difference is wording is not significant. Article 14 of the Model reads as follows:
Income derived by a resident of a Contracting State in respect of professional services or other independent activities of a similar character shall be taxable only in that State unless he has a fixed base regularly available to him in the other Contracting State for the purpose of performing his activities. If he has such a fixed base, the income may be taxed in the other Contracting State but only so much of it as is attributable to that fixed base.