ARTICLE 21
Professors
(1) An individual who visits a Contracting State for the purpose of teaching or carrying out research at a university, college or other recognised educational institution in that State and who is or was immediately before that visit a resident of the other Contracting State shall be exempt from taxation in the first-mentioned State on remuneration for such teaching or research for a period not exceeding two years from the date of his first visit for that purpose, provided that such remuneration is derived by him from outside that State.
(2) The provisions of paragraph (1) of this Article shall not apply to income from research if such research is undertaken not in the public interest but primarily for the private benefit of a specific person or persons.