Grey (gray) literature has been defined as:
"That which is produced on all levels of government, academics, business and industry in print and electronic formats, but which is not controlled by commercial publishers." (taken from http://www.greylit.org/about)
Grey literature may include reports, conference proceedings, technical standards or documents from all levels of government - essentially anything that is not created with commercial publication in mind.
Is it 'grey' or 'gray'? You may want to try using both as a search term. 'Grey' is the Canadian/British spelling; 'Gray' is the American spelling.
Grey literature is not always easy to find - that's what makes it 'grey'! A search engine like Google, Google Scholar or Bing (or whatever your favourite one is) may be the best tool to use. Expect to have to do some digging.
Good places to start include:
- government agencies that are relevant to your topic (see the 'Government' tab for some ideas)
- associations within the field (see the 'Websites' tab for some ideas)
In addition to the general starting points listed in the "How to Find Grey Lit' box, the following sites might be useful.