State Practice: Research Guides & Background Information
Sources of State Practice in International Law (Ralph Gaebler and Maria Smolka-Day, eds., 2002-) is one of the best places to start researching the practice of other countries. It outlines the sources that provide evidence of state practice for about 15 countries.
Researching Public International Law provides guidance for finding the state practice of other countries (click on “Custom and State Practice”).
The National Treaty Law and Practice series published by the American Society of International Law includes volumes that cover about 15 countries.
To find materials on the state practice of individual countries, search library catalogs with the subject heading international law [country].