Grey literature is an umbrella term for the wealth of literature and publications that fall outside of the traditional peer-reviewed journal article. This can include things like posters, conference proceedings, government reports, white papers, clinical trials, preprints, and more.
A scoping review is meant to reflect the state of the literature on a given topic. Given that so much of the scholarly conversation happens in grey literature, it is considered best practice to include grey literature whenever relevant in scoping reviews.
That being said, grey literature is a broad field and can be hard to find, so the goal is to identify 1-2 places that are going to have the most relevant grey literature for your topic and focus on searching those places.
Note that many databases include some amount of grey literature, such as dissertations. Be sure not to use limiters such as "peer reviewed" in these databases, or you will exclude relevant grey literature from your search results.
The sources below represent the most commonly used grey literature sources. If you want to see a more complete list of grey literature sources, lick on the Grey Literature Source tab in the navigation menu.
Source: https://guides.library.cornell.edu/evidence-synthesis/grey-literature
Dissertation/Thesis
Author last name Author’s first initials. Title of Book [dissertation]. Place of college or university: Name of college or university; year of completion.
Online Government/Organization Report
Author(s) or responsible body. Title of report. URL. Published date. Updated date. Accessed date.
Online Conference Proceeding/Presentation
Author(s). Title of presentation. Name of society meeting or conference; date of meeting or conference; place of meeting or conference. URL. Accessed date.
News Publications
Author(s). Title. Name of Newspaper. Publication date. Accessed date. Website address.
Websites
Author(s). Title. Name of website. Publication date. Updated date. Accessed date. URL