Independent Personal Services
(1) Income derived by a resident of a Contracting State from independent personal services or other activities of an independent nature shall be taxable only in that State. However, such income may also be taxed in the other State if such a resident habitually has a fixed base for the purpose of performing his activities in the other Contracting State, or his stay in the other Contracting State extends to a period or periods aggregating 183 days or more during the calendar year. If he has a fixed base or remains in that other State during the period or periods previously referred, that income shall be taxable in the other State but only so much that is attributable to a fixed base or they themselves have derived from the other State during the period or periods previously referred.
(2) The term "professional services" includes, in particular, scientific, literary, artistic, educational, or teaching activities, as well as the independent activities of physicians, engineers, architects, dentists, architects and accountants.