|Forms of Grey/Gray Literature|
The Fourth International Conference on Grey Literature (GL '99) in Washington, DC, defined grey literature as follows: "That which is produced on all levels of government, academics, business and industry in print and electronic formats, but which is not controlled by commercial publishers."
Gray literature is an important source of information. Though not scholarly, it is produced by researchers and practitioners in the field. It can often be produced more quickly, have greater flexibility, and be more detailed than other types of literature. "Gray literature serves scholars and lay readers alike with research summaries, facts, statistics, and other data that offer a more comprehensive view of the topic of interest (Weintraub)."
For more information about gray literature, try IL Toolkit-Finding Information: Gray literature.