What is the Grey Literature?
In general, grey literature publications are non-conventional, fugitive, and sometimes ephemeral publications.
They may include, but are not limited to the following types of materials:
- reports (pre-prints, preliminary progress and advanced reports, technical reports, statistical reports, memoranda, state-of-the art reports, market research reports, etc.)
- theses, conference proceedings
- technical specifications and standards
- non-commercial translations
- technical and commercial documentation
- official documents not published commercially (primarily government reports and documents
Source: The New York Academy of Medicine, http://www.greylit.org/about