(1) Payments which a student, business apprentice or trainee who is or was immediately before visiting a Contracting State a resident of the other Contracting State and who is present in the first-mentioned State solely for the purpose of his education or training receives for the purpose of his maintenance, education or training shall not be taxed in that State, provided that such payments arise from sources outside that State.

(2) A professor or teacher who visits one of the Contracting States for the purpose of teaching or engaging in research at a University or any other similarly recognised educational institution in that State and who, immediately before that visit was a resident of the other Contracting State shall not be taxed by the first-mentioned State in respect of remunerations received for such teaching or research for a period not exceeding two years from the date of his first arrival in that State for such purpose, provided that such payments arise from sources outside the first-mentioned State.

(3) Paragraph (2) of this Article shall not apply to income from research, if such research is undertaken not in the public interest but primarily for the benefit of a person or persons or for the purpose of business profit.