Gray literature is the information created by organizations such as government agencies, professional associations, research institutes, and think tanks that are not published in scholarly journals or books. This includes:

• Technical papers
• Government reports
• White papers
• Theses & Dissertations 
• Conference Proceedings
• Pre-print journal articles

Gray literature is produced by researchers and practitioners in a field and is an important component of a thorough literature review due to its depth and breadth, timeliness, flexibility, and open access.