Artikel 20

1. An individual who is a resident of a Contracting State immediately before making a visit to the other Contracting State and who, at the invitation of any recognised university, college, or other similar educational institution or scientific research institution, visits that other Contracting State for a period not exceeding two years from the date of his arrival in that other State solely for the purpose of teaching or research or both at such educational or research institution, shall be taxable only in the first-mentioned State on any remuneration derived from such teaching or research.
2. 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.