253. Union Centralization among Advanced Industrial Societies: An Empirical Study Bookmark Format Data archive or collection
254. Union Centralization Among Advanced Industrial Societies: An Empirical Study of Organisation for Economic Co-operation and Development (OECD) Countries, 1950-2000 Bookmark Format Series - completed
256. United Nations Surveys of Crime Trends and Operations of Criminal Justice Systems (1970+) Bookmark Format Series - ongoing
257. United States Citizenship, Involvement, Democracy (CID) Survey, 2006 Bookmark Format Single study