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 Contracting State unless the individual has a fixed base regularly available in the other Contracting State for the purpose of performing these activities. In such a case, the income received from such activities may be taxed in the other State but only so much of it as is attributable to that fixed base.
(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.