Sources of international law

Treaties

• Council of Europe Treaty Series
• HeinOnline Treaties and Agreements Library
• Max Planck Encyclopedia of Public International Law
• Oxford Public International Law, 50th Anniversary: Vienna Convention on the Law of Treaties
  • To celebrate the VCLT’s golden anniversary, OPIL has put together a collection of articles and chapters exploring its origins and entry into force, as well as an assortment of commentary on some of the current debates such as treaty terminations, Article 62, and the obscure doctrine of rebus sic stantibus. All content is free to read until 31st July 2019.
• UN Audiovisual Library of International Law. The Law of Treaties
  • The Lecture Series contains a permanent collection of lectures of enduring value on virtually every subject of international law given by leading international law scholars and practitioners from different regions, legal systems, cultures and sectors of the legal profession. Lectures on the Law of Treaties (Depositary Functions; Interpretation and Registration) by Ms. Annebeth Rosenboom and Mr. Jan Klabbers.
• United Nations Treaty Collection
• International Law Commission, Analytical Guide to the work of the ILC on Subsequent Agreements and Subsequent Practice in Relation to Interpretation of Treaties, Seventieth Session, 2018.
• International Law Commission, Analytical Guide to the work of the ILC on Provisional Application of Treaties, Seventieth Session, 2018.

Case-law

UN Declarations and Resolutions

The resolutions and decisions of the United Nations General Assembly and Security Council may provide valuable information on treaties and the law on treaties. Although they cannot themselves constitute international law or serve as conclusive evidence of a rule of customary law, such resolutions do have value in providing evidence of existing or emerging law. This point of view has been acknowledged by the International Law Commission.

As every Member State has been recognized and has a vote in the UN General Assembly, finding General Assembly resolutions that passed unanimously or near-unanimously may serve as an excellent starting point in the legal research process. Pay attention to the language of the resolution. Those with firm obligations versus those that are merely aspirational or advisory in nature are more likely to be considered valuable as evidence of customary international law.

→ Official Document System Search. ODS is the UN's Official Document System. You can search for UN declarations, resolutions and other documents by keywords, then narrow your search.

→ Start Your Research: (7) Resolutions and Decisions of International Organizations.

Soft law

Reference works

• Aust, A., Modern Treaty Law and Practice, New York, Cambridge University Press, 2013.
• Barrett, J., and R. Beckman, Handbook of Good Treaty Practice, Cambridge, Cambridge University Press, 2020.
• Cannizzaro, E. (et al.) (eds.), The Law of Treaties Beyond the Vienna Convention, Oxford, Oxford University Press, 2011.
• Chesterman, S. (et al.) (eds.), The Oxford Handbook of United Nations Treaties, Oxford, Oxford University Press, Forthcoming Aug. 2019. [PDF].
• Corten, O, and P. Klein (eds.), The Vienna Conventions on the Law of Treaties: A Commentary, Oxford, Oxford University Press, 2011.
• Dörr, O., and K. Schmalenbach (eds.), Vienna Convention on the Law of Treaties: a Commentary (2nd ed.), Heidelberg , Springer, 2018.
• Gardiner, R., Treaty Interpretation (2nd  ed.), Oxford, Oxford University Press, 2017.
• Hollis, D.B. (ed.), The Oxford Guide to Treaties, Oxford, Oxford University Press, 2020.[E-book].
• Klinger, J. (et al.) (eds.), Between the Lines of the Vienna Convention?: Canons and Other Principles of Interpretation in Public International Law, Alphen a/d Rijn, Kluwer Law International, 2019.
• Kolb, R.,The Law of Treaties. An Introduction, Cheltenham, Elgar, 2016.
• Linderfalk, U., On the Interpretation of Treaties: The Modern International Law as Expressed in the 1969 Vienna Convention on the Law of Treaties, Dordrecht, Springer, 2007. 
• Oliveira Mazzuoli, V. de, Direito dos tratados, 2a̲ edição revista, atualizada e ampliada, Rio de Janeiro, Editora Forense, 2014.
• Oliveira Mazzuoli, V. de, The Law of Treaties: A Comprehensive Study of the 1969 Vienna Convention and Beyond, Rio de Janeiro, Editora Forense, 2016.
• McNair, A.D., The Law of Treaties, Oxford, The Clarendon Press, 1961.
• Villiger, M.E., Commentary on the 1969 Vienna Convention on the Law of Treaties, Leiden, Nijhoff, 2009.

Selected books and articles

• Alvarez-Jimenez, A.,"The International Court of Justice's Use of the Vienna Convention in the Interpretation of Boundary Agreements 2000-2010", Journal of International Dispute Settlement, (2012), pp. 409-433.
• d'Aspremont, J., “The Treaty in International Law: Icon, Text, and Progeny” (March 16, 2019), Forthcoming, in D. Hollis (ed.), The Oxford Guide to Treaties (2nd ed., Oxford University Press, 2020). [PDF].
• Azaria, D., “Secret Treaties in International Law and the Faith of States in Decentralized Enforcement”, AJIL Unbound, 111 (2018), pp. 469-473. [E-article].
• Azaria, D. "The Legal Significance of Expert Treaty Bodies Pronouncements for the Purpose of the Interpretation of Treaties", International Community Law Review, Vol. 22 (2020), No. 1, pp. 33-60. [E-article].
• Bhat, S.S., “A Study of the Issue of ‘Relevant Rules’ of International Law for the Purposes of Interpretation of Treaties under Article 31(3)(c) of the Vienna Convention on the Law of Treaties”, International Community Law Review, 21 (2019), No. 2, pp. 190-219.
• Bianchi, A., D. Peat, and M. Windsor (ed.), Interpretation in International Law, Oxford, New York, Oxford University Press, 2015.
• Binder, C., and C.M. Brölmann, “The Law of Treaties Before Domestic Courts and Human Rights Bodies”, in A. Reinisch and R. Janik (eds.), International Law in Domestic Courts Casebook, Oxford University Press, 2018, Forthcoming; Amsterdam Law School Research Paper No. 2017-41; Amsterdam Center for International Law No. 2017-27, Oct. 2017. [PDF].
• Bjorklund, A.K., “The Enduring but Unwelcome Role of Party Intent in Treaty Interpretation”, AJIL Unbound, 112 (2018), pp. 44-48. [E-article].
• Bowman, M.J., and D. Kritsiotis (eds.), Conceptual and Contextual Perspectives on the Modern Law of Treaties, Cambridge, Cambridge University Press, 2018. [E-book].
• Bradley, C.A., “Treaty Signature”, in D. Hollis (ed.), The Oxford Guide to Treaties, Oxford, Oxford University Press, 2012, pp. 208-219. [E-article].
• Bradley, C.A., “Exiting Congressional-Executive Agreements”, Duke Law Journal, 67 (2018), No. 8, pp. 1615-1645. [E-article].
• Buga, I., Modification of Treaties by Subsequent Practice, Oxford, Oxford University Press, 2018. [E-book].
• Chatinakrob, T., “The Significance of Subsequent Agreements and Practice of the 1969 Vienna Convention on the Law of Treaties in the Development of International Law: The Analysis of the Notable Navigational and Related Rights and Whaling Decision”, Journal of Law, Policy and Globalization, 74 (2018), pp. 26-36. [PDF].
• Crawford, J., “The Current Political Discourse Concerning International Law”, Modern Law Review, 81 (2018), No. 1, pp. 1-22. [PDF].
• Crootof, R., “Change Without Consent: How Customary International Law Modifies Treaties”, Yale Journal of International Law, 41 (2016), No. 2, pp. 237-299.
• Crootof, R., “Jurisprudential Space Junk: Treaties and New Technologies”, in C. Giorgetti and N. Klein (eds.), Resolving Conflicts in the Law: Essays in Honour of Lea Brilmayer, Leiden, Brilll Nijhoff, 2019. [PDF].
• Djeffal, C., “The International Court of Justice: Peacemakers and Disputants”, in ibid., Static and Evolutive Treaty Interpretation: A Functional Reconstruction, Cambridge, Cambridge University Press, 2015, pp. 214-271.
• Djeffal, C., Static and Evolutive Treaty Interpretation: A Functional Reconstruction, Cambridge, Cambridge University Press, 2016.
• Donaldson, M., “The Survival of the Secret Treaty: Publicity, Secrecy, and Legality in the International Order”, American Journal of International Law, 111 (2017), No. 3, pp. 575-627. [E-article].
• Dothan, S., “The Three Traditional Approaches to Treaty Interpretation: A Current Application to the European Court of Human Rights”, iCourts Working Paper Series No. 141 (August 30, 2018); Fordham International Law Journal, 42 (2019), No. 3, pp. 765-794. [PDF].
• Durand, P., “How and why the European Union Makes Reservations to International Agreements”, Common Market Law Review, 55 (2018), No. 5, pp. 1387-1422.
• Fitzmaurice, M., and P. Merkouris, Treaties in Motion: The Evolution of Treaties from Formation to Termination, Cambridge, Cambridge University Press, 2020. [E-book].
• Fitzmaurice, M., “Third Parties and the Law of Treaties”, Max Planck Yearbook of United Nations Law, 6 (2002), pp. 37-137.
• Fitzmaurice, M., “Concept of a Treaty in Decisions of International Courts and Tribunals”, International Community Law Review, 20 (2018), No. 2, pp. 137-168. [E-article].
• Ginsburg, T., “Objections to Treaty Reservations: A Comparative Approach to Decentralized Interpretation”, in A.E. Roberts (et al.) (eds.), Comparative International Law, New York, NY, Oxford University Press, 2018, pp. 231-250. [E-article].
• Gowlland-Debbas, V., "The Role of the International Court of Justice in the Development of the Contemporary Law of Treaties", in C.J. Tams and J. Sloan (eds.),  The Development of International Law by the International Court of Justice, Oxford, Oxford University Press, 2013, pp. 25-52.
• Hafner, G., and G. Novak, “State Succession in Respect of Treaties”, in D.B. Hollis (ed.), The Oxford Guide to Treaties, Oxford, Oxford University Press, 2012, pp. 396-427.
• Helfer, L.R., “Terminating Treaties”, in D.B. Hollis (ed.), The Oxford Guide to Treaties, Oxford, Oxford University Press, 2012, pp. 634-649.
• Helfer, L.R., “Treaty Exit and Intra-Branch Conflict at the Interface of International and Domestic Law”, in C.A. Bradley (ed.), The Oxford Handbook of Comparative Foreign Relations Law, Oxford, Oxford University Press, 2018, Forthcoming. [E-article].
• Hosseinnejad, K., “Critical Evaluation of the ICJ Approach in Evolutionary Interpretation”, Iranian Review for UN Studies, 1 (2018), pp. 119–44. [PDF].
• Hulme, M.H., "Preambles in Treaty Interpretation", University of Pennsylvania Law Review, 164 (2015), No. 5, pp. 1281-1343.
• Linderfalk, U., “Treaty Abuse: Why Criticism of the Doctrine is Unfounded”, Journal of International Dispute Settlement, 9 (2018), No. 2, pp. 254–290. [E-article].
• Kolb, R., The Law of Treaties: An Introduction, Cheltenham, UK : Northampton, MA, USA, Edward Elgar Publishing, 2016.
• Lo, Chang Fa, Treaty Interpretation Under the Vienna Convention on the Law of Treaties: A New Round of Codification, Singapore, Springer, 2017.
• McInerney, T.F., Strategic Treaty Management: Practice and Implications, Cambridge, United Kingdom, Cambridge University Press, 2015.
• Mertenskötter, P., and R.B. Stewart, “Remote Control: Treaty Requirements for Regulatory Procedures", NYU School of Law, Public Law Research Paper No. 18-27 (March 21, 2018); Forthcoming in Cornell Law Review, 104 (2018). [PDF].
• Merkouris, P., "Interpreting the Customary Rules on Interpretation", International Community Law Review, 19 (2017), No. 1, pp. 126-155.
• Mitchell, A.D., and T. Voon, “The Rule of Necessary Implication”, 2017 draft for inclusion in J. Klingler (et al.) (eds), Canons of Construction and Other Interpretive Principles in Public International Law, Wolters Kluwer, 2018 (Forthcoming). [PDF].
• Murphy, S.D., The Relevance of Subsequent Agreement and Subsequent Practice for the Interpretation of Treaties, in G. Nolte (ed.), Treaties and Subsequent Practice, Oxford, Oxford University Press 2013, pp. 82-94.
• Nyarko, J., “Giving the Treaty a Purpose: Comparing the Durability of Treaties and Executive Agreements”, March 2018. [PDF].
• Pergantis, V., The Paradigm of State Consent in the Law of Treaties: Challenges and Perspectives, Cheltenham, Edward Elgar Publishing, 2017.
• Popa, L.E., Patterns of Treaty Interpretation as Anti-Fragmentation Tools: A Comparative Analysis with a Special Focus on the ECtHR, WTO and ICJ, Cham, Springer, 2018.
• Popa, L.E., “The Holistic Interpretation of Treaties at the International Court of Justice”, Nordic Journal of International Law, 87 (2018), No. 2, pp. 249-343.
• Ranganathan, S., Strategically-Created Treaty Conflicts and the Politics of International Law, Cambridge, Cambridge University Press, 2014.
• Sloss, D.L., The Death of Treaty Supremacy: An Invisible Constitutional Change, New York, NY, Oxford University Press, 2016.
• Szabó, M. (ed.), State Responsibility and the Law of Treaties, The Hague, Eleven International Publishing, 2010.
• Tams, C.J., A. Tzanakopoulos, A. Zimmerman (Eds.), Research Handbook on the Law of Treaties, Cheltenham, Edward Elgar, 2014.
• Törber, G., The Contractual Nature of the Optional Clause, Oxford, Hart Publishing, 2015.
• Verdier, P.-H., and M. Versteeg, “Separation of Powers, Treaty-Making, and Treaty Withdrawal: A Global Survey”, in C.A. Bradley (ed.), Oxford Handbook of Comparative Foreign Relations Law, 2019, Forthcoming; Virginia Public Law and Legal Theory Research Paper No. 2018-56. [PDF].
• Villiger, M., "The 1969 Vienna Convention on the Law of Treaties: 40 Years After", 344 Recueil des cours (2011), pp. 9-192.
• Waibel, M., “The Origins of Interpretive Canons in Domestic Legal Systems”, University of Cambridge Faculty of Law Research Paper No. 27/2018; Forthcoming in J. Klinger (et al.) (eds.), Between the Lines of the Vienna Convention: Canons of Construction and Other Interpretive Principles in Public International Law: A Practitioners' Handbook. [PDF].
• Watts, A., The International Law Commission 1949-1998 ; Vol. 4: Treaties, Final Draft Articles, and Other Materials, Oxford, Oxford University Press, 2010.
• Xiouri, M., The Breach of a Treaty. State Responses in International Law, Leiden, Brill Nijhoff, 2021. [e-book]
• Zarbiyev, F., “The ‘Cash Value’ of the Rules of Treaty Interpretation”, Leiden Journal of International Law, 32 (2019), No. 1, pp. 33-45.

Periodicals, serial publications

• A Complete Collection of the Treaties and Conventions, and Reciprocal Regulations, At Present Subsisting between Great Britain and Foreign Powers, and of the Laws, Decrees and Orders in Council Concerning the Same; So Far as They Relate to Commerce and Navigation, to the Repression and Abolition of the Slave Trade; and to the Privileges and Interests of the Subjects of the High Contracting Parties
• A Guide to the United States Treaties in Force
• Air Laws and Treaties of the World
• Australian Treaty Series
• Bulletin of Treaty Information
• Compilation of Treaties in Force
• Competent National Authorities Under the International Drug Control Treaties
• Consolidated Native Law Statutes, Regulations, and Treaties.
• Consolidated Treaty Series
• Council of Europe Treaty Series = Série des Traités du Conseil de l'Europe.
• Current Treaty Index ... : A Cumulative Index to the United States Slip Indexes and Treaties
• Der Friedensvertrag; Zeitschrift für Rechts- und Wirtschaftsfragen
• Estado de los Tratados y Convenciones Interamericanos = Status of Inter-American Treaties and Conventions = Relação dos Tratados e Convenções Interamericanos = État des Traités et des Conventions Interaméricains
• European Conventions and Agreements
• European Journal of International Law 24 (2013), No. 4.
• Eur-lex
• European Treaty Series
• Guide to Treaties in Force
• Hein's United States Treaties and Other International Agreements Current Microfiche Service
• Hertslet's Commercial Treaties: A Complete Collection of the Treaties and Conventions, and Reciprocal Regulations, at Present Subsisting Between Great Britain and Foreign Powers
• Intellectual Property Laws and Treaties
• International Treaties and Conventions ... : Texts of International Treaties and Conventions in the Preparation of Which Australia Participated But to Which Australia Did Not become a Party During
• Labour Law Documents : Treaties and Legislation on Labour and Social Security
• Law and Treaty Series (Pan American Union)
• List of Treaties Submitted to the Senate
• Overenskomster Med Fremmede Stater (Norway)
• Recueil des Traites de la France
• Recueil des Traités et Accords de la France
• Recueil des Traités et Conventions Conclus Par le Royaume des Pays-Bas Avec les Puissances Étrangères, Depuis 1813 Jusqu'à Nos Jours
• Recueil des Traités et des Engagements Internationaux Enregistrés par le Secretariat de la Société des Nations = Treaty Series : Publication of Treaties and International Engagements Registered With the Secretariat of the League of Nations
• Recueil des Traités et des Engagements Internationaux Enregistrés par le Secrétariat de la Societé des Nations Treaty Series and International Engagements Registered With the Secretariat of the League of Nations
• Recueil International des Traités du XXe Siècle : Contenant l'Ensemble du Droit Conventionnel Entre les États et les Sentences Arbitrales (Textes Originaux avec Traduction Française).
• Registro de Tratados (Spain)
• Relación de los Tratados y Convenciones Panamericanos = Status of the Pan American Treaties and Conventions = Relacão dos Tratados e Convenções Pan-Americanos = État des Traités et des Conventions Panaméricains
• Répertoire de Traités Internationaux et d'Actes Législatifs = Chronology of International Treaties and Legislative Measures
• Serie Sobre Tratados (Pan American Union)
• Signatures, Ratifications, Acceptances, Accessions, etc. Concerning the Multilateral Conventions and Agreements in Respect of Which the Secretary-General Acts as Depository
• Sino-foreign Treaties
• Statement of Treaties and International Agreements
• Statutory Compilation of the Indian Law Survey. A Compendium of Federal Laws and Treaties Relating to Indians
• Studies on the Law of Treaties
• Sveriges Internationella Överenskommelser
• Sveriges Överenskommelser Med Främmande Makter
• Tax Treaties Between Developed and Developing Countries Report
• Taschenbuch der Noten, Pakte und Verträge
• Three Centuries of Treaties of Peace and Their Teaching
• Tractatenblad van het Koninkrijk der Nederlanden
• Traités Internationaux et Actes Législatifs
• Tratados Publicos y Acuerdos Internacionales de Venezuela
• Travaux Préparatoires of Multilateral Treaties
• Treaties and Agreements With and Concerning China 1894-1919
• Treaties and Other International Acts of the United States of America
• Treaties and Other International Agreements of the United States of America, 1776-1949
• Treaties and Other International Acts Series
• Treaty Information Bulletin
• Treaties in Force : A List of Treaties and Other International Acts of the United States in Force
• Treaty Series (New Zealand)
• Treaty Series (OAS)
• Treaty series (Pakistan)
• Treaty Series (UN)
• United Nations Treaty Collection
• United States Treaties and Other International Agreements
• Verträge der Bundesrepublik Deutschland. Serie A, Multilaterale Verträge

Bibliographies

Dictionaries

• P.H. Rohn,World Treaty Index, Santa Barbara, American Bibliographical Center-Clio Press, 1974.