"information produced on all levels of government, academics, business and industry in electronic and print formats not controlled by commercial publishing i.e. where publishing is not the primary activity of the producing body."
- Grey Literature Network Service
It can be a great source of information from organizations working in the field.
Center for Conservation Innovation - Defenders of Wildlife
Google search tips
Organizations and sites of interest
Tip: look for a Publications or Research link
Before performing a Google search, select the settings link from the bottom right corner and then select "advanced search". From there, limit to a specific domain, such as .gov, or .edu. You can also limit by file type .pdf to find documents.