Grey literature is another form of literature sourced from nontraditional formats and publications. See below for additional definitions of grey literature provided by organizations and scholars affiliated with the field.
"Grey literature includes trial registries (discussed below), conference abstracts, books, dissertations, monographs, and reports held by the Food and Drug Administration (FDA) and other government agencies, academics, business, and industry."
"Grey literature is information produced outside of traditional publishing and distribution channels, and can include reports, policy literature, working papers, newsletters, government documents, speeches, white papers, urban plans, and so on."
The Third International Conference on Grey Literature in Luxembourg
"Grey Literature is a field in library and Information science that deals with the production, distribution, and access to multiple document types produced on all levels of government, academics, business, and organization in electronic and print formats not controlled by commercial publishing i.e. where publishing is not the primary activity of the producing body."
"The term ‘grey literature’ is often used to refer to reports published outside of traditional commercial publishing. Review authors should generally search sources such as dissertations and conference abstracts."
[Gray literature is] "foreign or domestic open source material that usually is available through specialized channels and may not enter normal channels or systems of publication, distribution, bibliographic control, or acquisition by booksellers or subscription agents."
From Farace & Schöpfel, 2010, p. 1-2
Grey literature is very frequently referred to when conducting extensive literature reviews and evidence syntheses. See the video below, developed by the University of Northern Colorado, for a helpful background and definition on grey literature.
Select the covers below to access eBooks available at Duquesne on the importance and use of grey literature. All are accessible via ProQuest Ebook Central.