Statute of the I.C.J., art. 38(1), sources of international law
The Statute of the International Court of Justice appears at the end of the Charter of the United Nations. Cite: Statute of the International Court of Justice, art. 38, ¶ 1.
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.
The Max Planck Encyclopedia of Public International Law contains articles about the various sources of international law, e.g., Customary International Law and General Principles of International Law. These and other relevant articles are listed under the subjects "Sources, foundations and principles of international law" and "Law of Treaties."
Other sources that may be relevant to your research
For selected books that may discuss the sources of international law, see the Getting started tab in this guide.