Grey literature usually refers to the information produced outside of traditional academic publishing. They may not be easily reachable by searching Google Scholar or major indexing databases.
Examples of grey literature include:
Grey literature can be an important source to support research in many disciplines. It helps researchers to:
Here are some resources to help you find different types of grey literature:
Visit this guide to find more sources of grey literature in health science.
Preprints are the author's original, unpublished versions of articles. There are plenty of preprint servers or repositories that collect preprints in different disciplines. You may find a (rough) list of them on this page.
Here are a few examples to help you find preprints:
These scholarly search engines also search for preprints:
Here are a few commonly used databases to find theses and dissertations, from PolyU and/or worldwide:
Check a full list of thesis databases here.
To look for government reports and reports that are available on websites, the quickest way is to Google and limit your search to a particular site or type of domain. You can use Google Operators to achieve this.
Here are some examples:
Limit to a domain:
Limit to a site with words in a URL:
Limit to a filetype:
To learn more about Google Operators, check out these sites:
Some article databases also cover conference papers. Here are a few examples: