Grey literature refers to research publications that are not regular journal articles or books. The most important examples are government documents such as reports, issues papers and policy documents, but also includes similar literature from non-government sources such as companies, NGOs, and UN agencies including WHO and UNESCO as well as theses, dissertations and conference papers that have not been peer-reviewed.
For more information to help with understanding and finding grey literature please refer to the 'Grey Literature' page in the Systematic Reviews Guide
