26 USC 5 - Cross references relating to tax on individuals
(a) Other rates of tax on individuals, etc.
(1) For rates of tax on nonresident aliens, see section 871.
(2) For doubling of tax on citizens of certain foreign countries, see section 891.
(3) For rate of withholding in the case of nonresident aliens, see section 1441.
(4) For alternative minimum tax, see section 55.