Public International Law

When looking for Customary International Law, your objective is to find evidence of state practice, such as:

1. records of a state’s foreign relations
2. domestic court decisions: Use the Foreign Law Guide to find sources for court decisions from other countries
3. domestic legislation: The Foreign Law Guide also points to sources for the legislation and codes of foreign countries
4. resolutions and declarations of internationall organizations: A profitable place to search is on the websites of these organizations. They generally provide a wealth of information as to their function and organization, not to mention links to an array of primary documents available online. The library links to many of these websites on our Research Tools page.
5. Another fruitful source for finding evidence of customary international law are international yearbooks. There is a collection of these yearbooks in HeinOnline's Foreign and International Law Resources Database

A wonderful starting point for researching this area of law is GlobaLex' research guide, Researching Customary International Law, State Practice and the Pronouncements of States regarding International Law.

James G. Apple, "What are General Principles of International Law?" 2 Int'l Judicial Monitor (July/Aug 2007: 

 When there is no provision in an international treaty or statute nor any recognized customary principle of international law available for application in an international dispute, the general principles of law can be used to “fill the gap.”