Researching International Law

Researching International Law


Judy Gire, Library Director


Sources of International Law

When researching international law issues, Article 38 of the International Court of Justice Statute lists the sources of international law in order of their weight as authority:

  1. International conventions and treaties
  2. International custom as evidence of a general practice accepted as law
  3. General principles of law recognized by civilized nations (doctrines of fairness and justice applied universally in legal systems throughout the world)
  4. Judicial decisions and teachings of the most highly qualified publicists

The first three sources are primary sources while judicial decisions and teachings of the most highly qualified publications are treated as secondary sources.

Getting Started

                Introductory Guides

·         International Legal Research in a Nutshell

Marci B. Hoffman & Robert C. Berring (Thompson-West  2008).

Designed for international legal research novices, this timely, succinct guide discusses the most important print and electronic sources readily available to anyone with access to a law library or the Internet.  Available  on Reserve in the library.

·         International and Foreign Legal Research: A Coursebook

 Marci B. Hoffman & Mary Rumsey (Martinus Nijhoff 2008).

Designed for classes in foreign and international legal research, this text can be used when a researcher needs information on an international law topic or source. Topics range from basic concepts of international law to particular international law subjects with emphasis on research strategies. Includes print and electronic sources. Available in Professor Gire’s office.

·         ASIL Guide to Electronic Resources for International Law: Introduction

Revised every six months, this is an excellent textual discussion of how to do international legal research on the Internet, highlighting important primary and secondary sources.

·         Academic Law Library Research Guides on International Law

Academic law libraries with strong international collections often provide international law research guides on their web sites designed to aid beginning researchers.  These guides are frequently geared to the library’s own collection.  Examples: Columbia, Duke, Harvard, UC Berkeley and Yale.

·         Globalex

Produced by Hauser Global Law School Program of New York University, Globalex includes high quality legal research guides on various international subjects as well as timely articles on international law topics and venues.

·         Law Library Resource Xchange –

This site includes a number of research guides on international law posted by law librarians as well as a search function.

                Online Tutorials for International Legal Research

·         CALI -- Private International Law Research (CALI Lesson LR77)

This 45 minute lesson by Tom Kimbrough is designed as a guide for students who are not familiar with researching private international law questions.

·         International Legal Research Tutorial

Duke University Law Library

This free online tutorial prepared by the Duke University Law Library offers basics of international legal research with emphasis on treaties and agreements, customary law and international organizations. Includes review questions.

                International Law Metapages           

American Society of International Law’s comprehensive site with links to law instruments, web sites and online research guides for international law.

Law Library of Congress portal to Internet links for reference sources for nations and regions.  Includes international sources.

Official United Nations web site section on international law with links to law-related U.N. bodies, U.N. Treaty Series, the ICJ and other international courts.

  • United Nations Dag Hammarskjold Library

Good place to access U.N. information and documents

International Law Blogs

·         Opinio Juris

·         IntLawGrrls


Check for international law treatises by leading authorities. Search by author and title if known or by subject heading or keyword in an online library catalog. Most international law treatises at UNH Law are classed under KZ.

·         MelCat

Online catalog of all UNH Law Library treatise holdings.

·         NELLCO Catalogs

Provides access to online catalogs of NELLCO member libraries including Harvard, Yale, Cornell, University of Pennsylvania, Columbia and NYU. Search individual library catalog or search combinations to identify relevant treatises.

·         Interlibrary Loan

See Librarian Kathy Fletcher if you need to interlibrary loan treatises not available in the UNH Law Library.

Periodical Articles

Many law reviews and journals include articles on international law topics which are sources for current information and citations to relevant material.

·         LegalTrac

Index of Anglo-American legal periodicals and law reviews. Search by author or title if known or by subject heading or keyword.  

·         Index to Foreign Legal Periodicals

Index to articles on foreign, comparative and international law published in legal periodicals and law reviews from around the world. Search by author, title, subject, keyword.

·         JSTOR

Full-text database of leading interdisciplinary academic journals.

·         Columbia International Affairs Online (CIAO)

Full-text collection of working papers, journal articles, books, policy briefs, research projects and conference proceedings discussing theory, policy and research of international affairs.

·         Interlibrary Loan

See Librarian Kathy Fletcher if you need to interlibrary loan periodical articles not available through the UNH Law Library.

Encyclopedias and ALR

·         Max Planck Encyclopedia of Public International Law

Authoritative encyclopedia on public international law topics written by scholars and practitioners from around the world.

·         ALR International

New ALR series devoted to collecting and analyzing relevant U.S. and foreign cases from English and non-English speaking countries on specific legal issues of international importance that have been litigated in the U.S. and global courts. Each annotation summarizes and analyzes the selected decision with references to additional relevant cases, jurisdictional table of cases, law and rules with cites to international decisions and research tips. Includes human rights cases. Available on Westlaw and in library’s print collection.

Treaty Research

Sources for United States Treaties

·         Hein Treaties & Agreements Library

Hein Online’s comprehensive collection of historical sources of United States Treaties includes: U.S. Statutes at Large, Bevan’s Treaties and Other International Agreements of the United States of America, United States Treaties and Other International Agreements, Treaties and Other International Acts Series and International Legal Materials. Fee-based.

·         International Legal Materials (I.L.M.), 1962-

This journal published by the American Society of International Law includes full-text of selected treaties and agreements. It is available on LexisNexis, Westlaw and Hein Online.

·         LexisNexis & Westlaw

LexisNexis and Westlaw have separate databases of U.S. treaties dating back to 1776 on LexisNexis and 1778 on Westlaw.

United States Treaty Indexing & Updating

·         United States Treaty Index: 1776-1990

Comprehensive print index to United States treaties kept current through a Current Treaty Index service with updating to the last 6 months. Available in library print collection.

·         Treaties in Force

Annual index prepared by the U.S. Department of State and available in print and electronically. Lists every bilateral and multilateral treaty the United States is a party to and indicates topic, parties, whether the treaty is still in force and sources of text. Also available in the Hein Treaties and Agreements Library and in separate databases on LexisNexis and Westlaw.

·         Guide to the United States Treaties in Force

Compiled by Igor Kavass, this annual print index to current United States treaties is similar in scope and format to the government’s Treaties in Force. It is also available in the Hein Treaties and Agreements Library.

·         Treaty Actions, 1997-

Updates Treaties in Force and available on the U.S. Department of State web site.

Judicial Interpretation of United States Treaties

·         American International Law Cases, 1783-

Specialized print reporter collecting federal and state cases relating to international law from 1783 to date. Available in library print collection.

·         Legal Research System for International law in U.S. Courts

Database of select United States court cases and related materials to aid legal professionals in identifying and understanding how international law is interpreted and applied by United States courts at the federal and state level.

·         West Digest Topic & Key Number Approach

Digest topic “Treaties” will yield United States cases dealing with treaties and international law topics

Legislative History of United States Treaties

·         Senate Treaty Documents

Hearings and debates of the Senate Foreign Relations Committee and transmittal messages from the President and Secretary of State to the Committee can provide evidence of “intent” behind a United States treaty.  The LexisNexis Congressional database is a good source for these documents.  

Sources of Treaties Where United States is Not a Party

·         United Nations Treaty Collection  

This collection includes:

                League of Nations Treaty Series (L.N.T.S.), 1920-1944

                Full-text of treaties registered with the Secretary of the League

                United Nations Treaty Series (U.N.T.S.), 1944-

This collection includes full-text of all bilateral and multilateral treaties registered with the Secretariat. Most comprehensive treaty series, but there can be time lags. 

·         Web Sites for Regional Organizations for Treaties

Check organization web sites such as the Council of Europe, Organization of American States for text of treaties of their member states. Many IGO’s have web sites containing text of regional treaties.

Status of Treaties Where United States is Not a Party

Checking for signatories, status, ratification and reservation information on treaties where the United States is not a party can be difficult. There is no one collection of links providing access to all relevant treaty information.  The United Nation’s Status of Multilateral Treaties Deposited with the Secretary-General is a good place to start but status information and reservations are limited to a small portion of the world’s treaties. Check databases or web sites provided by treaty secretaries and depositories for regional organizations.

Customary International Law

“Customary international law develops from the practice of States. To international lawyers ‘the practice of states’ means official governmental conduct reflected in a variety of acts, including official statements at international conferences and in diplomatic exchanges, formal instructions to diplomatic agents, national court decisions, legislative measures or other actions taken by governments to deal with matters of international concern.”  (Thomas Buergentahl & Sean D. Murphy, Public International Law in a Nutshell  22-23 (4th ed. 2007).

Evidence of a state’s practice is found in: (1) treaties; (2) decisions of national and international courts; (3) national legislation; (4) opinions of national legal advisors; (5) diplomatic correspondence; and (6) practice of international organizations.

Yearbooks of States and Organizations

                Yearbooks published by individual countries and by intergovernmental organizations provide a good way to assess information on state practice. They can note important legislation, case law and diplomatic practice involving international law.  Check library online catalogs and web sites for countries and IGOs. 

·         HeinOnline Foreign & International Law Resources Database

Includes prominent yearbooks from around the world in PDF format as well as a digest of U.S. practice in international law.

Sources for United States Practice

·         Digests of Practice

Series of digests first published in 1877 act as encyclopedias of United States international law practice. The last published was Whiteman’s Digest of International Law covering 1940s-1960s. Available in the library’s print collection and in HeinOnline’s Foreign & International Law Resources Database.

·         Digests of U.S. Practice in International Law, 1973-

These digests supplement the earlier digests and cover smaller time periods.

Available in the library’s print collection and in HeinOnline’s Foreign & International Law Resources Database.

·         Foreign Relations of the United States

epartment of State’s official documentary historical record of major United States foreign policy decisions and significant diplomatic activity. Also available in library’s print collection.

·         Restatement (Third) of Foreign Relations Law of the United States, 1987.

Unofficial, but respected summary of United States law and practice in international law and foreign relations. Available on LexisNexis and Westlaw and in library’s print collection.

Judicial Decisions

                Includes decisions of courts as well as international tribunals.

·         International Court of Justice (ICJ), 1947-

Source of text of decisions and activities of the most significant international court. Decisions also available on LexisNexis and Westlaw and in HeinOnline’s Foreign & International Law Resources Database.

·         Check web sites of other international tribunals such as the International Criminal Court for text of decisions.

·         Oxford Reports on International Law

Includes four modules of case law from international courts and dispute settlement bodies: (1) International Courts of General Jurisdiction; (2) International Criminal Law; (3) International Human Rights; and (4) International Law in Domestic Court. For each module you can view a list of the decisions as a while or those decisions coming from a particular jurisdiction or dispute settlement body.


Last revised:  January 2011