Suppose you are a scholar that has a contract at a university in state S for less than 2 years, and you are resident in your home country, say Italy. Then you successfully apply for tax treaty benefits, and your income in state S is not taxed.
If S is the US the controlling section is found in Article 20. If If S is New Zealand the controlling section is found in Article 20.
Are you supposed to pay taxes in Italy on your US income?
Are you supposed to pay taxes in Italy on your New Zealand income?
I am asking this as the two articles are worded a bit differently, and in particular the former does not explicitly require the US income to be taxed in Italy.