Independent Personal Services
(1) Income derived by a resident of a Contracting State in respect of professional services or other independent activities of a similar character shall be taxable only in that Contracting State, unless he has a fixed base regularly available to him in the other Contracting State for the purpose of performing his activities. If he has such a fixed base, the income may be taxed in the other Contracting State, but as much as it is attributable to that fixed base.
(2) The term "professional services" includes especially independent scientific, literary, artistic education or teaching activities as well as the independent activities of physicians, lawyers, engineers, architects, accountants and dentists.
(3) For the purposes of this Convention, the term "fixed base" means a fixed place such as an office or room, through which the activity of an individual performing independent personal services is wholly or partly carried on.