§ 2033.
The value of the gross estate shall include the value of all property to the extent of the interest therein of the decedent at the time of his death.
([Aug. 16, 1954, ch. 736], [68A Stat. 381]; [Pub. L. 87–834, § 18(a)(2)(A)], Oct. 16, 1962, [76 Stat. 1052].)