There are three types of UN information sources that people who do UN legal research are concerned with:
The Dag Hammarskjöld Library has some great research guides for doing UN research
These materials are divided into three broad categories: documents, publications, and official records.
A symbol serves as a unique identifier for a United Nations document. Each symbol is composed of numbers and letters which do not give any significant indication of the subject of a document. All language versions of a document carry the same symbol. Guide to UN Document Symbols.
The United Nations began publishing documents in electronic format in 1993. Most documents issued before 1993 are not yet available in electronic format.
All resolutions of the Principal Organs have been digitized and are available through the Official Document System, UNBISnet, and through various websites, including the UN Documentation: Research Guide.
All Security Council plenary documents have been digitized. Security Council documents, 1946-present, are now available in English, French and Spanish, through the Official Document System and UNBISnet.
In addition to documents published 1945-1993 that have not yet been digitized, many other UN publications are only available in print.
The Yearbook of the United Nations is the principal reference work of the United Nations and provides a detailed overview of the Organization's activities during the course of a year. Although the Yearbooks are now available online, many researchers find them easier to use in print, due to the size and format of the volumes. The Yearbooks provide citation to the documentation, include the full text of resolutions, and help researchers to identify relevant documentation.
UNBISnet is the library catalogue of the UN Library in New York. In addition to the holdings of the Library, it provides access to full text links to all language versions of recent documents 1993-present, and citations to documents 1979-present, which may or may not be available online. Metadata for older documents is added regularly, and links are added as the digital version of documents become available. UNBISnet provides a powerful search on the metadata of the UN documents.
ODS covers all types of official United Nations documentation, beginning in 1993. Older UN documents are, however, added to the system on a daily basis. ODS also provides access to the resolutions of the General Assembly, Security Council, Economic and Social Council and the Trusteeship Council from 1946 onwards. The system does not contain press releases, UN sales publications, the United Nations Treaty Series or information brochures issued by the Department of Public Information.
International Tribunal for the Law of the Sea (ITLOS) (Link to Cases, Basic Texts, and Publications of ITLOS)
See United Nations Research Guide on Treaties http://www.un.org/Depts/dhl/resguide/spectreat.htm
Under Article 102 of the Charter of the United Nations, every treaty and international agreement entered into by a Member State of the UN shall be registered with and published by the Secretariat. Regulations to give effect to Article 102 were adopted by the General Assembly in 1946 and subsequently modified a number of times. Pursuant to the mandate contained in Article 102, the United Nations Treaty Series (UNTS) was created.
The UN Treaty Series exists today in print and online, as part of the United Nations Treaty Collection (http://treaties.un.org/). The site overview includes definitions of key terms as well as a glossary of terms relating to treaty actions.