are hereby made effective beginning January 1, 1952, in any case in which such natural resource royalties, real property rentals, interest, patent royalties, copyright royalties, film rentals, and the like are derived from sources within the United States, or in which such dividends are derived from a United States corporation, by a nonresident alien (including a nonresident alien individual, fiduciary, and partnership) who is resident in Ireland for the purposes of Irish tax, or by a foreign corporation whose business is managed and controlled in Ireland, if such alien or corporation is subject to Irish tax on such income and at no time during the taxable year in which such income is so derived had a permanent establishment within the United States.
26 C.F.R. §513.7