Key U.S. federal tax primary sources:
U.S. Tax Treaties
See guide tab: U.S. Tax Treaties/Agreements
See Congress.gov: ArtI.S8.C1.1 Taxing Power + Jasper L. Cummings, Jr., The Supreme Court, Federal and State Taxation, and the Constitution (2d ed. 2022).
Internal Revenue Code (codified in 26 United States Code)
Westlaw: Title 26 Internal Revenue Code provides a current, annotated version of the Internal Revenue Code. (Source = United States Code Annotated)
Checkpoint Edge also provides a current, annotated version of the Internal Revenue Code. (Source = Internal Revenue Code (RIA))
See guide tab: Internal Revenue Code.
Treasury Regulations (first published in Federal Register; "general and permanent" regulations codified in 26 Code of Federal Regulations)
Tip: A "Treasury Decision" (TD or T.D.) = a final or temporary regulation (See Internal Revenue Manual, Part 32, section 188.8.131.52.5 available here)
See guide tab: Regulations, Revenue Rulings.
Court Decisions (federal tax cases begin in U.S. Tax Court, U.S. District Court or U.S. Court of Federal Claims; courts that hear appeals are U.S. Courts of Appeals > U.S. Supreme Court)
Westlaw: Tax Cases provides a search feature for all available tax cases + links (on right) to search American Federal Tax Reporter (RIA); U.S. Supreme Court Tax Cases; U.S. Courts of Appeals Tax Cases; U.S. District Courts Tax Cases; U.S. Court of Federal Claims Tax Cases; and U.S. Tax Court Cases. Link: U.S. Tax Court Cases includes subcollections: U.S.. Tax Court Division Opinions; Memorandum Opinions; and Summary Opinions.
See guide tab: Subscription Databases.
Free online sources of cases include U.S. Supreme Court > tab: Opinions (scope: Term 10/1991-) and U.S. Tax Court > tab: Orders & Opinions (scope: 05/01/1986-). Note: U.S. Courts Federal Court Finder often links to court sites that provide recent opinions and links to PACER (see Manage Your Account box for a description of PACER registration and billing). BLS students who wish to conduct in-depth tax case law research should consult guide tab: Subscription Databases.
Internal Revenue Service (IRS) guidance (e.g., Revenue Rulings and Revenue Procedures published in Internal Revenue Bulletin/Cumulative Bulletin)
The IRS publishes Revenue Rulings, Revenue Procedures, Notices and Announcements in its Internal Revenue Bulletin/Cumulative Bulletin. It provides taxpayer-specific rulings and determinations (Private Letter Rulings and Determination Letters), Technical Advice Memoranda and Chief Counsel Advice material at its Written Determinations page.
Westlaw: Tax Administrative Decisions & Guidance provides searchable collections of IRS Revenue Rulings, Revenue Procedures and Private Letter Rulings.
See guide tab: Regulations, Revenue Rulings.
Useful free sites:
The IRS provides: an organizational chart; Tax Code, Regulations and Official Guidance; a Tax Professionals page of online tools/information (path: Stay Compliant > Understand Your Responsibilities links to Circular No. 230, Regulations Governing Practice before the Internal Revenue Service); a Tax Pro News and Resources page (with instructions to subscribe to weekly e-News for Tax Professionals); and information about IRS-Sponsored Continuing Education Programs.
Tax Notes Research: Federal is a searchable collection of many federal tax primary sources and additional material (e.g., public comments on regulations).
Subscription databases that include tax reporters (e.g., Checkpoint Edge & Westlaw: U.S. Tax Reporter + VitalLaw: Standard Federal Tax Reporter) often are highly useful research starting points. Tax reporters provide primary law and analysis. They also highlight new developments. A search in Checkpoint Edge's "Federal" tax page can be a useful way to identify current, pertinent primary authority, commentary and news on an unfamiliar federal tax topic.
See description of U.S. Tax Reporter in guide tab: Subscription Databases > box: CheckPoint Edge. See description of Standard Federal Tax Reporter (2022) in guide tab: Subscription Databases > box: VitalLaw.
Helpful secondary sources:
Helpful secondary sources include: practitioners' guide Federal Tax Coordinator 2d in Checkpoint Edge; legal treatises (e.g., Mertens Law of Federal Income Taxation and additional federal tax treatises in Westlaw); articles; research papers/reports; and news sources.
Starting points for U.S. tax policy research:
At Tax Policy, the U.S. Department of the Treasury provides an explanation of the current U.S. Administration's revenue proposals, selected Office of Tax Policy reports and Office of Tax Analysis working/technical papers. Starting points to find articles, books and additional material include: pre-prints of articles and book chapters retrievable by keyword searches (e.g., fiscal policy/policies, tax policy/policies, tax discrimination, tax racism) in free Social Science Research Network; articles indexed under tax policy in free Tax Law Commons; published legal articles indexed under tax policy in subscription Current Index to Legal Periodicals; and material classified by subject headings: Fiscal Policy - United States and Racism - Economic Aspects - United States in BLS Library's SARA catalog. Researchers also can search by these subject headings in WorldCat (a "catalog of catalogs" available through SARA). Dean Paul L. Caron highlights websites of tax policy groups on the Resources page of Tax Prof Blog. Research guides also are useful. See the tax policy conferences/institutes listed on pp. 38-39 of Federal Income Tax Law: A Legal Research Guide (2nd ed. 2021); the examples of policy-focused tax research/documents on pp. 8-9 of Tax Research Techniques (10th ed. 2015); and Georgetown Law Library's Tax Policy Research Guide.
See also guide tabs: News and Articles & Research (in particular: Tax Policy & Advocacy page of AICPA; Tax Policy Center of Urban Institute and Brookings Institution, NBER Working Paper Series; and National Tax Journal).
Below are detailed print federal tax research guides available in Brooklyn Law School (BLS) Library's "Reference" collection. (Request at first-floor circulation desk.) Georgetown Law Library also provides Tax Research - Federal Guide and New York University Law Library offers the guide Federal Tax Research. Dean Caron's TaxProf Blog includes a Resources page to assist tax professors and students.