Sec. 154. Cross references. (1) For definitions of “husband” and “wife”, as used in section 152(b)(4), see section 7701(a)(17).

(2) For deductions of estates and trusts, in lieu of the exemptions under section 151, see section 642(b).

(3) For exemptions of nonresident aliens, see section 873(b)(3).

(4) For exemptions of citizens deriving income mainly from sources within possessions of the United States, see section 931(e).