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Grey Literature


Grey literature is "Information produced on all levels of government, academics, 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."

Grey literature can be useful for your research, but finding resources requires different tactics than you'd use for commercially published materials. This is because many types of grey literature are not indexed in some of the more common research tools like PubMed, CINAHL, Scopus, etc. 

Schnopfel J. Towards a Prague definition of grey literature. Presented at: Twelfth International Conference on Grey Literature: Transparency in Grey Literature. Grey Tech Approaches to High Tech Issues. Prague, 6-7 Dec 2010, Czech Republic. pp.11-26. Available from:

Types of Grey Literature

There are many types of grey literature that may be helpful to your research.

  • Conference abstracts and presentations
  • Proceedings
  • Government publications
  • White papers
  • Dissertations & theses
  • Patents
  • Regulatory data
  • Unpublished trial data
  • Policy papers
  • Annual reports

Why use Grey Literature?

Grey Literature can be hard to find, but it's a powerful tool to include in your research. Some benefits include:

  • Balanced Evidence. Studies with negative results, that were not commercially published.
  • Clinical Trial Details. Reports are often more detailed than the publications.
  • Publication Lag. Conference proceedings and abstracts will often appear months or years before peer-reviewed publication.

Paez, Arsenio. “Gray literature: An important resource in systematic reviews.” Journal of evidence-based medicine vol. 10,3 (2017): 233-240. doi:10.1111/jebm.12266

Web Searches

When searching for gray literature in a web browser (i.e. Google, DuckDuckGo, Firefox, etc.) you can limit your search to specific fields.

Search Operators
I want to see... Search Operator What it Does Example Searches
Government Resources insite:

Limits your search to a specific website and/or domain

Common domains of interest for gray literature in the United States are .gov and .org

  • Sarcoma AND
  • Sarcoma AND
Documents, Spreadsheets, Images, Presentations filetype:

Limits results to the file types you specify. Make sure to use caution and only access documents from trustworthy sources.

Example file types include: PDF, DOC, DOCX, PPT, PPTX, XLS, XLSX, etc.

  • Sarcoma AND filetype:pdf