26 C.F.R. § 1.673(c)-1 Reversionary interest after income beneficiary's death.
Title 26 - Internal Revenue
The subject matter of section 673(c) is covered in paragraph (b) of §1.673(a)–1.
Title 26: Internal Revenue
PART 1—INCOME TAXES
grantors and others treated as substantial owners
§ 1.673(c)-1 Reversionary interest after income beneficiary's death.