Below we list some sources for multidisciplinary repositories of grey literature, organized by country.
Unlike academic databases, multidisciplinary grey literature search engines are few and far between. Nevertheless, since 2008, a conference on grey literature repositories has been held annually in the Czech Republic, resulting in the formation of NUSL, The National Repository of Grey Literature, created between 2008-2011. At the 12th International Conference on Grey Literature (GL12) held in Prague, December 2010, several authors within the international grey literature community collaborated together on an e-book, Grey Literature Repositories, produced by NUSL and the National Technical University in Prague.
Maastricht University in the Netherlands, the country where the international grey literature community (GreyNet) was formed in 1993, created GLIN (Grey Literature in the Netherlands), an open access database of grey literature produced in that country.
Grey literature is often considered a supplement to academic database searching. The University of Edinburgh’s Grey Literature resource highlights this complementing relationship between the published and unpublished literature by introducing databases, such as Web of Science, known to be particularly strong at retrieving conference proceedings, as well as providing a list of Grey Literature Labelled Sources. From a repository perspective, these include The Grey Literature Report, OpenGrey, links to several theses databases, concluding with the World Health Organization (WHO) Institutional Repository (RIS).
Crossing the Atlantic, two organizations within the United States focusing on grey literature repositories should be noted: Texas Christian University, with an alphabetized list of several report and review-producing agencies across the nation, as well as the University of Chicago, which has compiled a comprehensive collection of association and other grey literature resources for its Masters in Health Professions Education Program.