A Treaty is a formal agreement between two or more countries.
There are two types of treaties:
A country may choose not to participate in a multilateral treaty.
Bevans = Treaties and Other International Acts of the United States of America 1776-1949.
KAV = Kavass numbers are a symbol, followed by a number, assigned for the temporary identification of treaties and agreements entered into by the United States after 1950 and not yet assigned a TIAS number. Used by the Hein current treaty service (available on HeinOnline). The Bluebook prefers KAV numbers if UST or TIAS are not available.
ILM = International Legal Materials
LNTS = League of Nations Treaty Series (1920-1946)
Stat. = Statutes at Large (prior to 1950, treaties were published as statutes)
TIAS = Treaties & Other International Act Series
UNTS = United Nations Treaty Series
UST = United States Treaties & Other International Agreements
In the United States, the President may enter into a treaty with another sovereign state with a 2/3 wote of the Senate.
The President also may enter into international agreements with another soverign by means of an Executive Agreement which does not require Senate approval.
Thus, researching treaties and other international agreements to which the United States is party may encompass the use of resources generated by the legislative or executive branches of government.
Only sovereign states or international organizations that are signatories to a treaty are legally bound by the terms of the treaty.
A signatory to a treaty may withdraw or legally terminate its participation in a treaty by complying with the conditions for withdrawal provided in the treaty. If conditions for withdrawal do not exist, or if a signatory does not comply with conditions for withdrawal that do exist, the signatory is said to abrogate the treaty.
Terms and provisions of a treaty may be changed after the treaty has been ratified and entered into force through a process called amendment.
Sovereign states and international organizations may request to be a party to a treaty after it has been entered into force by the original signatory states through a process called accession.
Germain’s Transnational Law Research (Law Library Reserves - K85 .G47)
Public international law in a nutshell (Law Library Reserves - KZ 3410 .B84 2007)
Restatement of the law, the foreign relations law of the United States (Law Library - KF 395 .A2 F6762 1992)
International Legal Materials (abbreviated as ILM - Law Library JX 68 .I5)
Marci B. Hoffman and Robert C. Berring, International legal research in a nutshell (Law Library Reserves KZ 1234 .H64 2008)
Encyclopedia of Public International Law (Law Library JX 1226 .E5 1992)
EISIL: The American Society of International Law’s Electronic Information System for International Law:
http://www.eisil.org/ contains primary documents and extremely helpful links to other documents on a wide variety of international law topics. This site is very helpful on basic principles of international law.