Tax Analysts - Lexis: WWLEG (1932-current)
Tax Analysts - Lexis: WWCASE (1890-current) - access worldwide tax court opinions
RIA - Westlaw: RIA-TREATIES (current) - treaties between the U.S. and others with legislative histories and editorial explanations (combination of RIA International Tax...
RIA - Westlaw: RIA-TAXTEX (current) - annotated analyses of treaties between the U.S. and other countries with citations to cases and rulings.
RIA - Westlaw: RIA-TAXT (current) - treaties between the U.S. and other countries, technical explanations, Senate Committee reports, Secretary of State reports and other...
Open access website contains bilateral treaties between the U.S. and foreign jurisdictions (in pdf).
Tax Analysts - Lexis: WWFRCE (1910-current) - treaties that are currently in force organized by country and subject matter (i..e. coffee, sugar, etc).
Tax Analysts - Lexis: TAWTT (1828-current) - worldwide tax treaties and U.S. legislative histories; many English translations.
Tax Analysts - Lexis: WWPROC file (1950-current) - more than 150 tax treaties as amended by protocols, exchanges of notes, etc. (treaties in file and current form)..