26 U.S.C. § 515: Taxes of foreign countries and possessions of the United States

The amount of taxes imposed by foreign countries and possessions of the United States shall be allowed as a credit against the tax of an organization subject to the tax imposed by section 511 to the extent provided in section 901; and in the case of the tax imposed by section 511, the term “taxable income” as used in section 901 shall be read as “unrelated business taxable income”.