Independent Personal Services
(1) Income derived by a person who is an individual or firm of individuals (other than a company) who is a resident of a Contracting State from, the performance in the other Contracting State of professional services or other independent activities of a similar character shall be taxable only in the first-mentioned State except in the following circumstances when such income may also be taxed in the other Contracting State:
- (a) if such person has a fixed base regularly available to him in the other Contracting State for the purpose of performing his activities; in that case, only so much of the income as is attributable to that fixed base may be taxed in that other State; or
- (b) if the person's stay in the other Contracting State is for a period or periods amounting to or exceeding in the aggregate 90 days in the relevant taxable year.
(2) The term "professional services" includes independent scientific, literary, artistic, educational or teaching activities as well as the independent activities of physicians, surgeons, lawyers, engineers, architects, dentists and accountants.