Bluebook Rule 21 covers citations to international materials. These include treaties, international cases of various sorts, and materials from the UN, EU, and WTO. Preferences and suggestions are tucked into introductory text and sub-sections, so careful editors will read closely.
Tables 3 through 5 outline which sources are preferred for international materials.
For tips on international law research, including source collection, check the Law Library's guide:
Do you have a partial or complete document symbol for a UN report, resolution, conference proceeding, or other document? Use the links below to quickly find it online.
Sample UN Document Symbol: A/CONF.151/26/Rev.1(Vol.I)