Columbia subject headings:
Income tax--Law and legislation--United States--Digests.
United States. Internal Revenue Service. Internal revenue bulletin--Indexes.
Harvard subject headings:
Income tax--Law and legislation--United States--Digests.
United States. Internal Revenue Service. Internal revenue bulletin--Indexes.
Princeton subject headings:
Income tax--Law and legislation--United States--Digests.
Indexes.
United States. Internal Revenue Service. Internal revenuebulletin--Indexes.