What is grey literature?
Grey literature is material that is not formally published by commercial publishers or peer reviewed journals and is produced by institutions, academics, organisations, and government agencies. It includes reports, unpublished data, conference proceedings, dissertations, policy and other documents and personal correspondence.
The advancement of the internet has made grey literature easily accessible electronically (e.g. PDF files and online data tables). Many organisations, institutions and agencies make grey literature available on their websites. There are also several grey literature databases which can be searched for references of data sources. Authors are often willing to provide the document of interest upon request, if the source is unavailable online.

Why use grey literature?
Peer reviewed literature and grey literature sources operate in relatively separate spheres with unique information in each. It is sometimes imperative to supplement information from peer reviewed literature with the information rich grey literature sources. Grey literature provides additional information not or not yet available in peer reviewed literature due to publication lag and publication bias.

The searches for grey literature that resulted in the first edition of this reference document were conducted in late 2007 and early 20084 as part of two larger projects being carried out at the National Drug and Alcohol Research Centre (NDARC) at the University of New South Wales, Sydney, Australia namely: Secretariat for the Reference group to the United Nations on HIV and injecting drug use and Mental Disorders and Illicit Drug Use Expert Group for the Global Burden of Disease project. A similar exercise was conducted in 2009 and additional sources of grey literature were identified.

These global reviews are being repeated for the Global Burden of Disease project, which is ongoing, and for work with a range of UN agencies involved in collating and reporting on data related to the epidemiology of illicit drug use and the associated health burden. An updated list of databases and websites is presented in this edition.

Searching for grey literature
Electronic search strategies were used to identify grey literature. The first step was to consult with a qualified research librarian about electronic databases that include grey literature sources for drug use and dependence. Many of these databases are listed as links on the National Drug and Alcohol Research Centre’s website. Additional databases and websites were found by consulting the related links pages on websites that were identified via search engines and recommendations from experts and colleagues.

In addition, the names of organisations responsible for collating state and national level statistics were identified from several reports and the corresponding websites were located where possible. Finally websites of all Ministries of Health and National AIDS commissions/programs were included in the search. The list of databases and websites was complemented with suggestions by experienced librarians and experts in the field of drug, alcohol and HIV/AIDS research.

Non-English websites
This report includes websites from countries across the world and therefore it is common that identified information is not presented in English. Google Translate was used to search these websites. Google Translate is a free and useful tool that can be used to translate Non-English websites into English (or other required languages). This is also a clever tool that can detect the language if you are not sure of the origin.

Additional information
In addition to websites and online databases, electronic forums or eForums (also referred to as eGroups, bulletin boards, discussion forums and message boards) can be an important portal for obtaining grey literature. There are two basic types of internet-based forums, one being web-based and the other email-based. They both are however topic-orientated discussion lists run by interest groups that are dependent on user-generated content. While eForums will rarely contain any grey literature per se the potential benefit lies in the ability to directly connect with a large audience of topic-orientated subscribers that may have important information that would not be accessible via conventional search engines.

The websites and corresponding addresses that are presented in this document were current at the time of publication. We acknowledge that addresses of sites may change, however, the descriptive information provided in this document will aid in finding websites that have been relocated following publication.

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