Centre for Economic Policy Discussion Papers
http://www.cepr.org/content/discussion-papers
Papers from a leading European research network in economics.  A network of economists, who are affiliated with but not employed by CEPR.  The focus is economic policy making in Europe and beyond.

Columbia International Affairs Online (CIAO)
Working papers from university research institutes and occasional papers series from NGOs, proceedings from conferences, journal articles, policy briefs, and more.

Congressional Research Service Reports (CRS)
Useful policy papers, on a wide range of international and domestic topics, prepared by the Library of Congress’ Congressional Research Service.   Available online 2004 to date.  Online indexing is provided from 1916 forward.  For the onsite availability of earlier reports (in microform), visit the above link. 

Archives of European Integration
http://aei.pitt.edu/
Two types of materials: certain types of independently-produced research materials and official European Community/European Union documents.
 

European Resea5ch Papers Archive
http://eiop.or.at/erpa/
Online working paper series in European Integration studies.

European Union Documentation Center
http://aei.pitt.edu/
University of Pittsburgh Collection Dates: 1951-2004
Essentially a "government documents" collection for both the organization currently known as the European Union and for its precursors: European Coal and Steel Community; European Atomic Energy Community; European Economic Community; European Communities.

German Information Network International Relations and Area Studies
http://www.fiv-iblk.de/eindex.htm
Bibliographic and full-text materials from a variety of research organizations (primarily European).  An effort of twelve independent German research institutes.    One of the largest bibliographic social science databases in Europe. Main subject areas covered are global and regional developments, foreign and security policy and social trends.  Searchable at: http://www.fiv-iblk.de/database/online_access.htm

NBER Working Papers
https://research.lib.buffalo.edu/NBER
National Bureau of Economic Research (NBER) researchers initially report their findings in scientific papers aimed at other professional economists in academic institutions, business, government, and the business media around the world. Nearly 500 NBER Working Papers are published each year, and many subsequently appear in scholarly journals.

Policy File – Not Held
http://www.policyfile.com/marketing/about.jsp
Offers access to policy papers and gray literature from over 350 U.S. think tanks and research institutes.  Europe and European nations are sometimes topics.