Grey literature refers to materials produced by governments, academics, businesses, and others that are not controlled by commercial publishers. It is difficult to acquire and index due to its transient nature and lack of bibliographic controls. Examples include technical reports, theses, newsletters, and standards. The British Library has a large collection of grey literature, especially reports, conference proceedings, and theses acquired since the 1950s. Grey literature can now be more easily found through search engines, portals, databases, and organizational websites thanks to the internet, though it remains obscure.

1. Grey Literature – a hidden resource Elizabeth Newbold Engineering Information for Today & Tomorrow November 22, 2006

7. Grey Literature Holdings at The British Library