All the subscription databases mentioned are available via the Electronic Law Library. Access to Westlaw International Materials is via Westlaw UK.
HeinOnline has a vast collection of recent and historical treaties, the World Treaty Library; it brings together the UN Treaty Series, League of Nations Treaty Series, United States treaties, the contents of the Consolidated Treaty Series and other sources.
HeinOnline also includes the UN Law Collection, which contains the United Nations Treaty Series (UNTS), the League of Nations Treaty Series (LNTS) and many pre-20th century treaties.
Lexis®Library has treaties involving the United States and a collection of tax treaties (Tax Analysts, Worldwide Tax Treaties).
Westlaw International has US treaties, EU treaties, RIA tax treaties and arbitration treaties.
IBFD Online has a collection of tax treaties.
See also: the UN Treaty website, the WordLII International Treaties Library, the websites of intergovernmental organisations (e.g. the Council of Europe, WIPO and UNCTAD), and national treaty websites (many national sites are listed by the Eagle-i law gateway: find them on Eagle-i by entering the name of jurisdiction, e.g. "france" and the word "treaties").
TIP: to trace a treaty, or to look up key details such as the UNTS citation or date of signature, try the FLARE Index to Treaties.
Justis includes the International Law Reports (ILR) series. ILR publishes cases from international courts and tribunals as well as international law cases from municipal (domestic) courts, 1919 onwards.
Oxford Reports on International Law (ORIL) has cases from many international courts, tribunals and UN bodies. It also has a module called International Law in Domestic Courts, comprising decisions by municipal courts from all over the world on points of international law, with translations of key passages and expert commentary. ORIL is similar to the ILR in many ways, but smaller.
Westlaw International Materials has cases from several international courts and tribunals, including the International Court of Justice (ICJ). Westlaw UK has the European Human Rights Reports.
Lexis®Library has ICJ cases; US cases on international law (under International Law, US Federal & Special Court Cases, Combined); international tax cases; and human rights cases.
HeinOnline has Permanent Court of International Justice (PCIJ) cases in the Foreign and International Law Resources collection and ICJ cases in the United Nations Law Collection.
Westlaw International Materials has arbitral awards by the London Court of International Arbitration, the International Centre for Settlement of Investment Disputes (ICSID), the International Chamber of Commerce, the WTO and various other bodies: see International Arbitration Materials, (right-hand side of International Materials homepage). Westlaw International Materials also has Iran-US Claims Tribunal Decisions, via the International Materials Index (not the International Arbitration page).
WorldTradeLaw.net is a specialist WTO database that brings together commentary on WTO/GATT decisions and the decisions themselves.
Lexis®Library has WTO/GATT decisions.
HeinOnline has Reports of International Arbitral Awards (RIAA). (This publication is also on the UN website).
Oxford Reports on International Law has an International Investment Claims module, covering cases from many different arbitral bodies, including ICSID, the ICC International Court of Arbitration, the London Court of International Arbitration and the Permanent Court of Arbitration.
Investment Arbitration Reporter, an e-journal found on the IALS Library Catalogue, contains news of investment arbitration decisions.
All the databases mentioned below are available via the IALS Electronic Law Library.
If you are looking for any articles on a particular international law topic, try these databases...
Westlaw UK, Journals screen: has a large number of full-text international/European law journals, plus abstracts from many more.
Westlaw International Materials: the World Journals collection has full-text journals published in the US, UK, Canada, Australia and elsewhere, including many titles specialising in international law.
Index to Legal Periodicals: indexes international law journals published in the US and elsewhere.
Index to Foreign Legal Periodicals: indexes many international law journals and yearbooks.
HeinOnline: see Law Journal Library, Foreign & International Law Resources Database and Harvard Research in International Law.
Lexis®Library: International Law Review Articles, Combined (most are from US journals); see also main (UK) journals screen on Lexis, which includes a large number of journals focusing on international law.
If you are looking for a specific article...
Search for the journal on the IALS Library Catalogue - if it is available online, there will be a link to the appropriate database. (N.B. Article titles are not listed on the Catalogue, only journal titles.)
Encyclopedias and books
The Max Planck Encyclopedia of Public International Law and the Max Planck Encyclopedia of Comparative Constitutional Law are both available online, via the Library Catalogue.
Cambridge Core includes over 700 international law e-books published by Cambridge University Press - see Library Catalogue for links to individual titles.
Oxford Scholarship Online includes more than 350 international law e-books (postgraduate level and above) published by Oxford University Press - see Library Catalogue for links to individual titles.
Elgaronline has about 100 international law e-books published by Edward Elgar - see Library Catalogue for links to individual titles.
HeinOnline's Legal Classics library includes over 100 classic treatises on international law. These titles are not listed individually on the Catalogue - to access them, open HeinOnline (from the Electronic Law Library), select 'Legal Classics', then browse by subject.
Brill Online's collection of more than 700 recent international law e-books is also available - see Library Catalogue for links to individual titles.