Independent Personal Services
(1) Income derived by a resident of one of the Contracting States in respect of independent professional services or other independent activities of a similar nature shall be taxable only in that State except in the following cases:
- (a) In case this resident habitually has, in that other Contracting State, a fixed base for the exercise of his or her activities. In such a case, only that part of the income which is attributable to the said base shall be taxable in the other Contracting State or
- (b) In case he is present in the other Contracting State for a period or periods of a total duration equal to or more than 183 days during the course of any period of 12 months. In such a case, only that part of the income arising from these activities carried out in the other Contracting State shall be taxable in the other State.
(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.