Article 52 specifies five categories of Omani-sourced income subject to tax when paid to non-residents: (1) Royalties, (2) Research and development fees, (3) Computer software use/rights, (4) Management or service fees, and (5) Dividends and interests. This tax is calculated on the gross amount paid or credited to the account of a non-resident person (as defined in Article 40). The specific tax rate for these categories is governed by Article 113. This provision forms the core of Oman's withholding tax (WHT) regime, targeting specific outflows to foreign entities.