26 C.F.R. § 301.6101-1
Period covered by returns or other documents.
Cite as 26 C.F.R. § 301.6101-1 (2026)
For provisions concerning the period covered by returns or other documents, see the regulations relating to the particular tax.
26 C.F.R. § 301.6101-1
Cite as 26 C.F.R. § 301.6101-1 (2026)