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Customary International Law

Pronouncements of Foreign States

Official Government Websites/Publications
Secondary sources that provide evidence of international custom
International Yearbooks

Yearbooks (sometimes called year books) are unofficial secondary sources of state practice. Many are available in English. Yearbooks tend to include the following types of publications on international law in that country:

  • reviews of the country's state practice with regard to international law
  • reports on legislation (full-text legislation)
  • reports on treaties (full-text treaties)
  • indexes of cases, reviews of cases (full-text cases)
  • book reviews
  • literature relating to international law
State Yearbooks
Multi-Jurisdictional Yearbooks
Yearbooks of International Organizations

Other Secondary Sources