Royalties and technical service fees: source State taxation permitted but limited when beneficial owner is resident in the other State. Article 12 permits both the source State and the recipient's State to tax royalties and fees for technical services arising in the source State, but limits source State taxation when the beneficial owner is resident in the other State. It defines royalties and fees for technical services, excludes specified categories, disapplies the source taxation rule where payments are effectively connected to a permanent establishment or fixed base of the beneficial owner, and requires arm's-length adjustment where related-party relationships inflate payments.