If it looks like a treaty, but...
...you can't find it in standard treaty tools and collections, it may be "soft law" and not a treaty. Soft law is non-binding, but may indicate the objectives and principles that states are willing to support publicly. Examples often come from the economic, environmental, social, and human rights areas and may include General Assembly resolutions, declarations, e.g., the Universal Declaration of Human Rights, codes of conduct, guidelines, programs of action, and documents resulting from international conferences. See "Soft law," in Parry & Grant Encyclopaedic Dictionary of International Law (3d ed. 2009).
Sources of soft law
Texts of "soft law" might be located in documents of the IGO or other body that sponsored the international conference from which the document emerged, in the publications and official documents or on the website of the organization, in books, articles or websites covering the topic.
Books, working papers, etc.
Law reviews, journals, articles