Income from immovable property taxable where the property is situated; definition includes usufruct and resource payment rights. Income from immovable property may be taxed in the Contracting State where the property is situated; immovable property is defined by the law of that State and includes accessories, usufruct and rights to payments for working mineral deposits and other natural resources, excluding ships, boats and aircraft; the rule applies to income from direct use, letting or other forms of use and also to income of an enterprise and to income used for performance of personal services.