"Information produced on all levels of government, academia, business and industry in electronic and print formats not controlled by commercial publishing i.e., where publishing is not the primary activity of the producing body" -ICGL Luxembourg definition, 1997- Expanded in New York, 2004
"Gray literature...refers to informally published written material (such as reports) that may be difficult to trace via conventional channels such as published journals and monographs because it is not published commercially or is not widely accessible." - Wikipedia definition of "grey/gray literature"
"Grey literature may not stand alone, but it can contribute substantively to understanding scientific challenges. [In scientific research] every source should be considered in the exploration of an issue. In some domains, the best source of information may be grey. Some grey literature goes through as stringent (or more) of a review as commercially published content." -Richard Huffine, National Library Coordinator, USGS
Finding grey literature can be difficult and require exhaustive searching. Since grey literature is not included in bibliographic databases, it requires different search techniques in order to find information relevent to your topic of interest. The links below offer quick introductions and tutorials, but a librarian is always a great place to start!
Google Advanced Search or Google Scholar Advanced Search - Use advanced search to improve precision. Access advanced search in Google Scholar from the menu in the top left of the page.Try date limits or domain limits (.org or .gov) to narrow results. You can also use Google Advanced Search to search a specific web site (bottom of advanced search page). Google is also a good way search for conference proceedings and meetings, ex.: concussions conferences.
Organizations are also a good method for finding grey literature. Identify organizations that are likely to create publications in your area of research, such as:
Once you have identified an organization of interest, you can generally locate publications on their Web site.
Organization Publishers from the Grey Literature Report: This is a list of hundreds of publishers and organizations that produce grey literature.
MedlinePlus Organizations: A List of health information organizations, including government agencies, foundations, professional societies, research associations, and disease support groups.
The Health and Medicine Division (HMD) Reports - The Health and Medicine Division (HMD) of the National Academies (formerly Institute of Medicine, IOM) publish reports that provide objective and straightforward advice to decision makers and the public. This site includes reports published after 1998.
Agency for Healthcare Research & Quality (AHRQ) - AHRQ provides data on the cost and use of health care, scientific information on health care and results of medical treatments, as well as data on special needs of priority populations.
BMC Proceedings is an online, open access journal publishing proceedings of conferences across all scientific and clinical disciplines, including peer-reviewed full-length articles, collections of abstracts and meeting reports.
The NTRS provides access to NASA's current and historical technical literature and engineering results. Over 500,000 aerospace-related citations, over 200,000 full-tect online documents and over 500,000 images and videos are available.
Directory of Open Access Repositories
Read more about Web of Science Conference Proceedings selection process