ARTICLE 21
Teachers and Researchers
(1) Any individual who visits a Contracting State at the invitation of that State, of a university, an educational establishment or any other non-profit cultural institution through a programme of cultural exchange for a period not exceeding two years for the sole purpose of teaching, giving conferences or carrying out researches in that institution, and who is or was immediately before that visit, a resident of the other Contracting State, shall be exempt from tax in the first Contracting State on the remuneration he receives in respect of such activity, provided that such remuneration is derived from sources outside that State.
(2) The provisions of paragraph 1, shall not apply to remuneration and income from research if such research is undertaken for persons and enterprises with business purposes.