International Legal Research

An introduction to researching public international law.

Sources of International Law

Article 38 of the Statute of the International Court of Justice lists the sources of international law.

1. The Court, whose function is to decide in accordance with international law such disputes as are submitted to it, shall apply:

a. international conventions, whether general or particular, establishing rules expressly recognized by the contesting states;

b. international custom, as evidence of a general practice accepted as law;

c. the general principles of law recognized by civilized nations;

d. subject to the provisions of Article 59, judicial decisions and the teachings of the most highly qualified publicists of the various nations, as subsidiary means for the determination of rules of law.

2. This provision shall not prejudice the power of the Court to decide a case ex aequo et bono, if the parties agree thereto.

This guide briefly examines each of these sources. For additional information, please consult separate research guides on U.S. Treaties and International Agreements, World Treaties, and United Nations Documents. The international law resources listed in these guides are available on the Internet or in the Mabie Law Library collection. Be sure to note the specific locations listed for individual items. If you need some help locating materials, please stop by Research Services.

Another discussion of the sources of international law appears in The Restatement of the Law (Third) The Foreign Relations Law of the United States, Sections 102, Sources of International Law, and 103, Evidence of International Law.

Internet Resources

EISIL (Electronic Information System for International Law):
Identification of and citations for major conventions in various international law topics; links to online texts

ASIL Electronic Resource Guide (ERG):
Society of International Law guide for selected public and private international law topics

Globalex (NYU):
Research guides on selected international law topics.

International Legal Research Tutorial (Duke and UC Berkeley)

International Justice Resource Center (
Links to books, articles, databases and other resources on human rights law, in particular

The websites of international organizations sometimes include research guides for their documentation and document numbering systems. Examples include:

Many additional research guides are available on the Internet. Use general terms such as international legal research or more specific terms -- treaty research, international courts and tribunals -- in internet search engines.


The following sources provide help in citing international sources and in deciphering citations:

The Bluebook: A Uniform System of Citation (20th ed.)
Bluebook Rule 21 on International Materials

Bluebook Tables
T.3 (Intergovernmental Organizations)
T.4 (Treaty Sources)
T.5 (Arbitral Reporters)
plus abbreviations for journals, case names, court names, etc.

Electronic Information System for International Law (EISIL;
Frequently Cited Treaties & Other International Instruments (Univ. of Minnesota)

NYU Journal of International Law and Politics
Guide to Foreign and International Legal Citations
Ask for the second edition of this guide at Research Services: K89 .G85 2009. The first edition is in Law Reference: K89 .G85 2006.

Prince's Bieber Dictionary of Legal Abbreviations
Available in print. Copies of the sixth edition are available in Law Reference: KF246 2009. Older editions are available in the law stacks.

Cardiff Index to Legal Abbreviations

Also search the law reviews databases on Westlaw and LexisNexis to see how treaties are being cited, then compare to your citation preferences.

Heafey Law Library Research Team