26 C.F.R. § 1.1016-1
Section 1016 and §§ 1.1016-2 to 1.1016-10 , inclusive, contain the rules relating to the adjustments to be made to the basis of property to determine the adjusted basis as defined in section 1011. However, if the property was acquired from a decedent before his death, see § 1.1014-6 for adjustments on account of certain deductions allowed the taxpayer for the period between the date of acquisition of the property and the date of death of the decedent. If an election has been made under the Retirement-Straight Line Adjustment Act of 1958 ( 26 U.S.C. 1016 note), see § 1.9001-1 for special rules for determining adjusted basis in the case of a taxpayer who has changed from the retirement to the straight-line method of computing depreciation allowances.
26 C.F.R. §1.1016-1