For distribution purposes, many documents of the United Nations are classified in the three following categories: general, limited and restricted.

1)  General: documents receiving full circulation. This designation is used on basic documents and final meeting records, including agendas, studies and reports, communications from Governments, resolutions and other decisions of main organs;

2)  Limited: documents for which wide circulation is unnecessary because of the temporary nature of the documents, such as draft resolutions, and amendments thereto, draft reports and other action documents. The designation "limited" is indicated by an "L" in the symbol. Some technical documents which are issued for delegates are issued as limited documents. These may contain important information of interest to researchers calling upon the services of the library. Documents in the limited category are generally available for a relatively short period of time. Therefore, it is advantageous to request limited documents not received through regular distribution, or additional copies of limited documents soon after the original document is issued, whenever this is feasible.

3)  Restricted: this designation applies exclusively to documents whose content requires that they be treated as confidential or that they be withheld from public circulation. The designation "Restricted" is indicated by an "R" in the symbol identifying the document. In general, libraries do not receive any documents designated as restricted, and researchers requesting them should be informed that they are not available. Nevertheless, it should be noted that some documents are derestricted after a period of time.