Don't forget to search the LIBRARY CATALOG (the search box in the middle of the library's home page) to help you find books, videos, articles related to your topic.
Grey literature includes things such as reports, white papers, policy documents -- things not published in traditional academic sources like books and journal articles. These are often written by staff members/experts at NGOs, government agencies, think tanks, etc. and can provide valuable information.
You can find grey literature in a number of places including: