The United Nations is making more and more of it's older publications available online through retrospective conversion. However, do not assume that what is online is all that exists. Refer to print indexes for historical UN documents
Non-partisan "think tank" that publishes Foreign Affairs; the site includes vast array of in-house publications (policy briefs, journal articles, etc) as well as external material focusing on international affairs and American foreign policy.
The UN Statistics Division oversees UN collection, organization and distribution of statistics and provides links to the UN databases from their web site. Here are some of the major UN statistical databases.