Grey literature refers to any information source that is not commercially published or undergone a specific peer-review process.
What counts as grey literature?
Internal reports, such as government white papers
Meeting minutes and notes
Think tank reports
Why use grey literature?
Often good quality information produced by experts in their field, e.g. white papers are commissioned by the government from a body of subject specialists
Providing important insights into the 'reality' of research, e.g. clinical trial data that is not published because the study was not successful and therefore not commercially beneficial
Reflects the expertise of individuals not associated with academia e.g. independent think tanks; charities representing oppressed groups or individuals; other industry experts (for example, in business or technology).
OpenGrey, System for Information on Grey Literature in Europe, is your open access to 1 014 872 bibliographical references of grey literature (paper) produced in Europe and allows you to export records and locate the documents. Examples of grey (gray) literature include technical or research reports, doctoral dissertations, some conference papers, some official publications, and other types of grey literature. OpenGrey covers Science, Technology, Biomedical Science, Economics, Social Science and Humanities.
NGO Search is a Google Custom Search that searches across hundreds non-governmental organization (NGO) websites. NGO Search is a project of the International Documents Taskforce (IDTF) and the Government Documents Roundtable (GODORT) of the American Library Association (ALA). This is a spreadsheet of NGOs included in the project.
International governmental organizations (IGOs) are organizations made up of more than one national government—examples include NATO (North Atlantic Treaty Organization) and the WHO (World Heath Organization). The governments are the members. IGO Search is a Google Custom Search that searches across IGO websites. It is a project of the International Documents Taskforce (IDTF) and the Government Documents Roundtable (GODORT) of the American Library Association (ALA). Here is the growing spreadsheet of IGO urls included in the search.