Peace Palace Library
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Research guide Customary International Law


According to Article 38 of its Statute, the International Court of Justice ‘whose function is to decide in accordance with international law such disputes as are submitted to it,’ has to apply, inter alia, ‘international custom.’ This source of public international law is described, in the same Article, as ‘evidence of a general practice accepted as law.’

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Library blog European Court of Auditors


A fiercely debated issue regarding the European Union (EU) is its budget and the allocation of funds, e.g. for agricultural subsidies. Every year one of the lesser-known European institutions, the European Court of Auditors (ECA), audits the Union’s revenue and expenditures. Furthermore ECA monitors if the annual facts and figures are reliable and if the transactions comply with the applicable European rules and regulations. This blog analyzes ECA’s legal position, formal tasks and its relationship with national Courts of Auditors.

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News and events Special Exhibition: “The Peace on Posters and the Posters on Peace”

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Syria Crisis: Humanitarian Law, Warfare, Refugees

The Syrian civil war is an ongoing multi-sided armed conflict in Syria in which international interventions have taken place. The war grew out of the unrest of the 2011 Arab Spring and escalated to armed conflict after President Bashar al-Assad’s government violently repressed protests calling for his removal. Violence in Syria has escalated amid an absence of meaningful efforts to end the war. A confidential list of individuals and units are believed to be responsible for crimes against humanity, breaches of international humanitarian law and gross human rights violations. We have created a Library Special on the Syrian civil war in order to provide you easy access to our collection. If you have any questions, please don’t hesitate to ask the librarian:

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South China Sea Territorial Disputes

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China claims most of the South China Sea, through which more than $5 trillion of world trade passes every year. Vietnam, Malaysia, Brunei, the Philippines and Taiwan have rival claims. In addition to substantial natural resources, the South China Sea is of paramount strategic significance to the Asian security paradigm and to global stability. We have created a Library Special on this topic in order to provide you easy access to our collection: a selective bibliography, newsletters, books, articles and online resources.

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Peace Palace Library showcase

  • 517-f-20

    517 F 20

  • s-2347-d-50

    S 2347 d.50

  • 9780198701958

    Orford, A., F.Hoffmann, & M.Clark, The Oxford Handbook of the Theory of International Law, Oxford, United Kingdom, Oxford University Press, 2016.

  • 9780198704218

    Green, J.A., The Persistent Objector Rule in International Law, Oxford, United Kingdom, Oxford University Press, 2016.

  • s-2422-d-38

    S 2422 d.38

  • s-2280-d-33

    S 2280 d.33

You can find the showcase in our Reading Room.