The following definition was given during The Twelfth International Conference on Grey Literature in Prague in 2010:
"Grey literature stands for manifold document types produced on all levels
of government, academics, business and industry in print and electronic formats
that are protected by intellectual property rights, of sufficient quality to be collected and
preserved by libraries and institutional repositories, but not controlled by commercial publishers;
i.e. where publishing is not the primary activity of the producing body."
Grey literature includes: presentations, conference papers and proceedings; unpublished trial data; official publications; research reports; theses and dissertations; data compilations etc.
Theses and Dissertations can be a great source of inspiration for your own dissertation topic. You can access millions of full-text dissertations and theses at USEK Library.
To do so, check the USEK Library catalog:
Or you can explore the 1.2 million full-text dissertations and theses available through ProQuest Dissertations and Theses Global.
The majority of USEK Library databases allow you to limit your search to Source type. See example below
Government documents are an important primary source of information on a wide range of topics. The majority of these documents can be found through government websites (with domain suffix: .gov)
Research reports includes the results of investigations or surveys, and are usually published by the body undertaking the research or the funder. this type of document can be found by searching the websites research organizations in addition to USEK Library’s databases.