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Grey literature

How to find grey literature

As grey literature is not published by mainstream publishers, it can be hard to find.

The Library has some older printed research reports from government departments, and some other bodies like the Royal Colleges. You can search the Library by keyword, individual name, and organisation.

Some research databases can also contain conference papers, theses, and technical reports. It’s worth looking in the subject databases lists or in the help section of a particular database to see what they cover.

Here are some online grey literature resources covering preprints, health sources, think tanks, charities and NGOs.

You could also look at our resource guides for finding government documents and official publications, statistics and data sources, technical reports, patents, and theses.

Multidisciplinary search engines

You can use these resources to discover many types of grey literature, although it may be difficult to get hold of the items if they are not available as open access documents:

  • BASE – Bielefeld Academic Search Engine
    BASE brings together journals, datasets, institutional repositories, theses and other collections of academic publications. Approximately 60% of the items are open access.
  • CORE search engine
    CORE is the world’s largest aggregator of open access research papers, deriving from thousands of repositories, journals and other web resources.
  • JISC Library Hub Discover
    Search the online catalogues of major libraries in the UK and Ireland
  • openDOAR
    openDOAR is a directory of open access repositories, including institutional, disciplinary and governmental repositories holding conference papers, reports, working papers, journal articles, books and more. You can browse by country or do an advanced search to find specific repositories.
  • WorldCat
    WorldCat searches the collections of more than 10,000 libraries worldwide

Preprint Repositories

A preprint is a version of a scholarly paper that has not yet been through the peer review process. Researchers can make a preprint available through a repository more quickly than they can publish a full journal article, and this enables research to be rapidly scrutinised and debated by the research community.

The major preprint repositories are:

  • ArXiv
    ArXiv hosts almost 2 million preprints in the fields of physics, mathematics, computer science, quantitative biology, quantitative finance, statistics, electrical engineering and systems science, and economics.
  • BioRxiv
    BioRxiv is a preprint server for biology research papers.
  • F1000 Research
    F1000 Research is an open publishing platform that also uses a transparent peer review process. Any researcher can upload their research outputs to the platform.
    IDEAS is an easy-to-use search tool to help you search and download papers from RePEc, which is an Economics database of over 3 million working papers, books, journal articles and software. Almost all the papers are freely available to read and download.
  • OSF
    OSF is an aggregated search tool which searches several preprint archives at the same time, including ArXiv, BioRxiv, RePEc and more.
  • SSRN
    SSRN is a multidisciplinary repository of working papers and preprints owned by the publisher Elsevier. Most papers can be downloaded free of charge.
  • Wellcome Open Research
    A platform for Wellcome-funded researchers to share research (including data, research findings, protocols and case reports) quickly. Papers undergo an open peer review process after they are posted to the platform, with all peer review comments being freely accessible to all users.
  • Zenodo
    Zenodo is an open access repository hosted by CERN. It includes preprints, journal articles, reports, datasets, software, presentations and other research outputs.

Health sources

Here are some UK sources of grey literature in the health sciences and healthcare:

Internationally, there is also the WHO IRIS (World Health Organisation Institutional Repository for Information Sharing), which contains technical reports, committee papers, journal articles and other reports and documents produced by the WHO and its regional offices.

Think tanks, charities, and NGOs

Many independent organisations make their publications available online, here are some places to look for grey literature from think tanks, charities and non-governmental organisations.

Think tanks

  • Find Policy
    this website provides customised searches for policy papers from curated collections of think tanks and commentators on climate, economy, foreign policy and more.
  • Harvard Think Tank Search
    this website provides a customised Google search designed to search for policy papers and other publications published on the websites of over 1,200 think tanks. You can also browse lists of think tanks around the world.
  • The Nuffield Trust
    The Nuffield Trust are a think tank producing research and analysis on health and social care in the UK.
  • Open Think Tank Directory
    Use this website to find think tanks and similar organisations focusing on a range of topics including gender, technology, social policy, infrastructure and more.
  • Think Tank Review
    A monthly annotated bibliography of selected EU-focused think tank papers, produced by the Library of the Council of the European Union.


Use these sources to find a charity, and then look on that charity’s website for its publications:

NGOs (non-governmental organisations)

    Open access collection of research and policy on global development issues.
  • UN Environment Programme
    Search or browse for data, factsheets and reports produced by the UN Environment Programme.
  • NBER Working Papers (US)
    The National Bureau of Economic Research is a US research network on Economics which publishes working papers produced by its researchers.