Artikel 20

1. Notwithstanding the provisions of Article 15, a professor or teacher who makes a temporary visit to a Contracting State for a period not exceeding two years for the purpose of teaching or carrying out research at a university, college, school or other educational institution and who is, or immediately before such visit was, a resident of the other Contracting State shall, in respect of remuneration for such teaching or research, be exempt from tax in the first-mentioned State, provided that such remuneration is derived by him from outside that State and such remuneration is subject to tax in that other State.
2. The provisions of this Article shall not apply to income from research if such research is undertaken not in the public's interest but wholly or mainly for the private benefit of a specific person or persons.