Capital gains taxation: source state may tax gains from immovable property and permanent establishment assets. Capital gains provisions allocate taxation by asset character and situs: immovable property and movable property of a permanent establishment or fixed base are taxable in the State where situated; ships and aircraft in international traffic are taxable only in the alienator's State of residence; shares deriving principally from immovable property may be taxed in the State where the property is situated; other shares may be taxed in the company's State of residence; remaining gains are taxable only in the alienator's State of residence.