Don't let the language confuse you ... treaties, conventions, agreements, protocols, etc., all have the same effect under international law and are often used interchangeably when talking about this type of source. The resources you consult to do this research will depend on two factors: 1) if the treaty is bilateral or multilateral, and 2) whether or not the United States is a party. Doing the research itself will look similar either way as you try to utilize indexes or secondary sources to find citations that lead you to the full text of a treaty. Once located, you need to determine the status of the treaty and if the language of the text is ambiguous, the treaty's drafting history. Pay special attention to the abbreviation for the various sources as that is how you will likely see them present in citations..