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International Law Research Guide: Sources of International Law

A research guide to help researchers locate and understand public and private international law resources.

About the Sources of International Law

The International Court of Justice (ICJ) identifies the sources of international law in the

Article 38 which reads:

  1. The Court, whose function is to decide in accordance with international law such disputes as are submitted to it, shall apply:
    1. international conventions, whether general or particular, establishing rules expressly recognized by the contesting states;
    2. international custom, as evidence of a general practice accepted as law;
    3. the general principles of law recognized by civilized nations;
    4. 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.

The primary sources you will use are:

  • Treaties (AKA international conventions)
  • Customary International Law (State practice combined with opinio juris)
  • General Principles of Law
  • Writings of Publicists
  • Judicial Decisions
  • Soft Law/Non-Legally Binding Instruments

Secondary Sources that Explain the Key Concepts of Sources of International Law.

Videos by esteemed scholars and practitioners:

UN Audiovisual Library of International Law: Sources of International Law [Anthony D'Amato]

Articles:

Books

Sources of International Law Theory

Books & Articles by sub-category

Customary International Law Theory
General Principles of Law
Writings of Publicists
Judicial Decisions
Soft Law/Non-Legally Binding Instruments

Finding Sources of International Law

To Find Treaties use:

To find Customary International Law (State practice combined with opinio juris), use

To Find General Principles of Law:

General principles can be determined from reliable secondary sources on foreign law. This is an exercise in comparing laws from different jurisdictions and looking for similarities.

To Find Writings of Publicists:

To Find Judicial Decisions:

To Find Soft Law/Non-Legally Binding Instruments:

General Principles of Law Research Recommendations

To Find Books in UC Law SF library on a foreign law topic, try searching for Law and the country name as a subject header and a key word related to the legal issue. Examples are provided below.

Some books provide comparisons of law from different jurisdictions. This series may provide you with a collection or articles about the principles of law across multiple jurisdictions.

If you are researching a constitutional law issue:

HeinOnline Provides an excellent Finding tool for Foreign Law Articles.

To quickly find relevant primary and secondary sources on a specific legal topic in another country, use:

If the Foreign Law Guide provides the name of a law or legal resource, but does not provide a direct link, you can try searching for the publication in the UC Law SF catalog.

Primary Law

To quickly compare law on a particular legal issue across multiple countries, use:

Writings of Publicists Research Recommendations

Writings of Publicists refers to commentary by respected scholars and practitioners of international law. This comes in the form of articles and books.
Research Guides and Citators are useful finding tools for discovering the titles of books or articles on your topic, by prestigious international law practitioners or scholars. Once you find the name of the publication, you will need to then look for it in UC Law SF databases or in the catalog.

Some databases for finding reliable information include:

Articles

Books

If the book you would like to use is not in the UC Law SF Catalog, you can look for it in WorldCat and then request it via ILL.