Grey literature is an important source of information.

Grey literature is defined as "information produced on all levels of government, academics, business and industry in electronic and print formats not controlled by commercial publishing" ie. where publishing is not the primary activity of the producing body." —ICGL Luxembourg definition, 1997. Expanded in New York, 2004

Types of Grey Literature

• Government Information
• Dissertations and Theses
• Conference Proceedings (select Conference Proceedings Citation Index)
• Newspapers and Magazines
• Think Tanks

Resources

• Alternative Press Index - Indexes periodicals, newspapers and magazines which report and analyze the practices and theories of cultural, economic, political, and social change. 
• Canadian Research Index (detailed citations to publications in the Microlog microfiche collection)
• GreySource - directory of organizations

Policy Reports and Working Papers

• Brookings Institute
• Canadian Public Documents Collection
• Conference Board of Canada e-Library  In addtion to the e-Library, look to particular Centres for research on specific topics.  Go to Conference Board of Canada and scroll down to the bottom of the page.  Select Sitemap. Under Special Projects you will see Centre for the North, Centre for Food in Canada, How Canada Performs, etc.
• National Bureau of Economics Research (NBER) Working Papers
• PolicyFile (U.S.)
• Social Research and Demonstraton Corporation A non-profit research organization, created specifically to develop, field test, and rigorously evaluate new programs.

Think Tanks

• ​Harvard Kennedy School provides a searchable database of more tha 590 think tanks and research centres.