Bevans = Treaties and Other International Agreements of the United States of America
I.L.M. = International Legal Materials
L.N.T.S. = League of Nations Treaty Series
T.I.F. = Treaties in Force
T.S. = Treaty Series
T.I.A.S. = Treaties and Other International Acts Series continues the Treaty Series.
U.N.T.S. = United Nations Treaty Series
U.S.T. = United States Treaties and Other International Agreements
Stat. = Statutes at Large
A treaty (sometimes called a convention, covenant, protocol, charter, pact, etc.) is an agreement between two or more nations or international organizations.
It may be bilateral (between two countries), or multilateral (between three or more countries). The treaty text may provide for the manner by which it takes effect. Often, the agreement will enter into force when it has been signed and ratified by a certain number of parties.
Electronic Information System for International Law (EISIL): Free online searchable database of international law information with links to relevant primary materials and authoritative web sites.
HeinOnline: The Treaties and Agreements Library includes PDF images of Statutes at Large, U.S.T., T.I.A.S, Bevans, Treaties in Force, and International Legal Materials. The United Nations Law Collection includes PDF images of U.N.T.S. and L.N.T.S.
U.S. Treaties on Westlaw (USTREATIES): Includes Statutes at Large, U.S.T., T.I.A.S, Bevans, Treaties in Force, and International Legal Materials
U.S. Treaties on LEXIS (INTLAW;USTRTY): Includes Statutes at Large, U.S.T., T.I.A.S, Bevans, Treaties in Force, and International Legal Materials.
United Nations Treaty Collection: Includes Multilateral Treaties Deposited with the Secretary-General and the United Nations Treaty Series.
Researchers can start with the convenient list maintained by Mary Rumsey of the University of Minnesota Law Library: Frequently-Cited Treaties and Other International Instruments.
Another useful trick is to search on the name of the agreement in the law review databases of Westlaw or Lexis. There will considerable variation, but it is usually not difficult to pick out the most accurate citation.
For formal citation, please refer to The Bluebook (Rule 21.4) or the ALWD Citation Manual (Rule 21).