There are a number of excellent, comprehensive research guides to international taxation law covering:
Two recommended guides are:
Some resources described in these guides are only available to those affiliated with the institution, however they also list many freely available materials.
International taxation journals (select list)
British Tax Review
EC Tax Review
International Tax Bulletin
Intertax: European Tax Review
Journal of Taxation
National Tax Journal
New Zealand Journal of Taxation Law and Policy
Tax Law Review
These international databases are useful for comparative taxation research as well as research on a specific topic:
Contains full-text journals, dissertations, working papers and country and industry focused reports.
Accounting, Tax & Banking Collection
Global scholarly journals in accounting, tax, banking and business
Business Source Complete
Full-text and peer reviewed journals covering accounting, banking and finance.
Covers a wide range of economics related literature.
Contains national, international and regional newspapers, news wires, podcasts and company reports.
The world's largest image-based legal research database.
Contains law reviews, legal newspapers and specialist publications.
Lexis Advance US
US federal and state law sources, international law and laws of some non-US jurisdictions. Select
Thomson Reuters Westlaw
Full-text cases, legislation and journal articles from a range of jurisdictions, but mostly US and Canada. Select
Contains cases, legislation, journals articles, commentary and EU legal materials.
Canadian cases and legislation can be found on CanLII.
The principal Act is the Income Tax Act, RSC 1985, (5th Supp) c1.
Hein Online contains the Canada Supreme Court Reports and the Revised Statutes of Canada.
Department of Finance Canada
Oversees the development of tax law and other measures, including legislation governing banks and other federal financial institutions.
Department of Justice: Income Tax Act
Includes regulations made under the Act and amendments not in force.
An excellent guide to UK taxation is Oxford LibGuides: Tax law from Oxford University Library.
The official site for UK legislation is legislation.gov.uk.
ICLR Online contains the Law Reports including Appeal Cases (AC), Chancery (Ch), Queen's Bench (QB) and King's Bench (KB), and the Weekly Law Reports (WLR).
Cases and legislation can also be found on BAILII.
An excellent guide to US taxation is Federal Tax Research: Outline & Guide Information from the New York University Law Library.
Cases and legislation are available from the Legal Information Institute (LII).
New Zealand Legislation is the official NZ legislation site.
Cases and legislation can also be found on NZLII.
The New Zealand Law Reports are available from Lexis Advance Pacific.
CPA Australia: New Zealand contains tax checklists, sample taxation letters and information on practising and auditing in New Zealand.