Cases:
Standard Federal Tax Reporter (library has 1945-2012). KF6285 .C67.
U.S. Tax Cases (library has 1935-2012). KF6280.A2 C63.
Tax Court Memorandum Decisions (library has 1942-1997). KF6280 .A2 C73.
United States Tax Court Reports (library has 1942 to present). KF6280 .A2 T37.
Statutes:
Title 26 of the United States Code comprises the "Tax Code." Consult U.S.C., U.S.C.S., or U.S.C.A. Other sources include:
Internal Revenue Acts (annual as needed, Thomson Reuters), including texts of Acts, Legislative History, Signing Statements, Tables, and Index. KF6275.99 U54 2012.
Internal Revenue Code (annual, Thomson Reuters), KF6276.526 .A19 I57 2014. Library has 1971 through 2014.
Regulations (Treasury Decisions, or T.D.s):
Title 26 of the Code of Federal Regulations comprises the codified Tax regulations. Other sources include:
Federal Tax Regulations, KF6301 .A4 2014.
Internal Revenue Bulletin & Cumulative Bulletin, KF6282 .A2 I495. Library has 1922 to 2012. Available online.
Treaties & International Documents:
U.S. International Taxation & Tax Treaties, by Rhoades & Langer. KF6306 .R48. Also available on Lexis.
If you are not finding the specified treaty in Rhoades & Langer, check the Treaties Collection on Hein Online.