A basic introduction to international legal research in the Peace Palace Library. Your road map for approaching an international legal research problem. Step 5.
Article 38(1)(d) of the Statute of the International Court of Justice sets forth that the Court shall apply 'the teachings of the most highly qualified publicists of the various nations, as subsidiary means for the determination of rules of law'. Historically, it was only the writings of highly qualified publicists that contained a discussion of a particular custom and how it emerged as evidence of customary international law. Nowadays, these teachings may be interpreted more broadly to include writings, lectures, and even audio-visual materials. Included are individuals who are highly specialised in the field of international law.
The International Law Commission states that the focus should be on 'eminent' writers, including expert bodies. There is no official list of these eminent publicists, but here are some examples that have been cited as such: Brierly, Brownlie, Crawford, Oppenheim, Shaw, American Law Institute, Institut de Droit International, International Law Association and the International Law Commission.
The legal researcher must now carry out research to assess a publicist's credentials and authority as well as the accuracy, objectivity, and rigor of the writing itself. In this, the quality of the writing and the author's methodology matter more than the author's reputation. The teachings of highly qualified publicists can be found in legal treatises or law reviews and in materials of the law institutes mentioned above. The use of these teachings as subsidiary means to determine rules of customary law is a challenging endeavour. While all subsidiary sources may also be used as secondary sources, the reverse is not always true.
The Peace Palace Library Catalogue is your gateway to resources. The Library offers access to all types of sources - electronically or in print, and covers all topics of international law. The Peace Palace Library Research Guides, prepared and maintained by our team of Law Librarians, are another powerful tool to find what you are looking for. The Research Guides suggest certain books, articles, databases and other materials considered indispensable for doing research on your specific topic.
You might consider our Library Instruction on how to conduct legal research in the Library at all levels.
References
- Deplano, R. and N. Tsagourias (eds), Research Methods in International Law: a Handbook, Cheltenham; Northhampton, 2021.
- Dumberry, P. "Article 38 of the ICJ Statute: Sources", in: Kulick, A. and M. Waibel (eds), General International Law in International Investment Law: A Commentary, Oxford, Oxford University Press, 2024, pp. 464-488.
- Guide to International Legal Research, Fifth Edition, Newark, LexisNexis Matthew Bender, 2003.
- Hoffman, M.B. and R.C. Berring Jr., International Legal Research in a Nutshell, Second Edition, St. Paul, West Academic Publishing, 2017.
- IALL Guidelines for Public International Law Research Instruction (Second edition, published September 2024)
- Kuehl, H.F. and M.A. O'Brien, International Legal Research in a Global Community, Durham, Carolina Academic Press, 2018.
- Lomio, J.P., H. Spang-Hansen and G.D. Wilson, Legal Research Methods in a Modern World: A Coursebook, Third Edition, Copenhagen, DJØF Publishing, 2011.
- Winer, A.S., M.A.E. Archer, and L. Louis-Jacques, International Law Legal Research, Durham, Carolina Academic Press, 2013.