Bluebook Rule 21.4.5(a) (i) and (ii) requires that you cite to one of the following official U.S. treaty sources (in order of preference). If the agreement has not appeared in one of these official sources, cite an unofficial source (see boxes below).
According to Bluebook rule 21.4.5(b), for agreements to which the United States is not a party, cite one source published by an international organization, if therein. If not, cite the official source of one signatory, if therein. If the treaty is not found in a signatory's treaty source, cite an unofficial treaty source.
While the Internet with its wealth of information is a good place to conduct basic research, it is not ideal for in-depth thorough legal research. It is the responsibility of each user to establish the validity, integrity, and reliability of information found on the Internet.
However, the Internet can be useful for locating some types of legal information such as current legal documents. It is important that the legal researcher use authoritative and reliable web sites for locating legal information and documents. Although the web pages listed here have been selected by a skilled reference librarian, the individual researcher is responsible for evaluating the web pages.
Evaluating Web Pages: Techniques to Apply & Questions to Ask is a good source on finding information on the Internet.