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. However, such income may be taxed in the other Contracting State if:
- (a) he has a fixed base regularly available to him in that other Contracting State for the purpose of performing his activities, but only so much of the income as is attributable to that fixed base may be taxed in that Contracting State; or
- (b) he is present in that other State for a period (or periods) exceeding in the aggregate 120 days within any twelve-month period; in that case, only so much of the income as is derived from his activities performed in that other State may be taxed in that 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.