ARTICLE 14
Independent Personal Services
(1) Income derived by a resident of a Contracting State in respect of professional services or other activities of an independent character shall be taxable only in that State unless he has a fixed base available to him in the other Contracting State for the purpose of performing his activities or he is present in the other Contracting State for a period exceeding in the aggregate 183 days in the calendar year concerned. If he has such a fixed base or remains in that State for the aforesaid period or periods the income may be taxed in that other State but only so much of it as is attributable to that fixed base or is derived in that other State during the aforesaid period or periods.
(2) The term "professional services" includes especially independent scientific, literary, artistic, educational or teaching activities as well as the independent activities of physicians, lawyers, engineers, architects, dentists and accountants.