Grey literature in open archives: how to identify it?
Integrating grey literature into a scientific and technical watch

Many institutions and organizations are now making their grey literature freely available online, including theses and dissertations, conferences, reports and working papers. Their share of institutional archives varies, but can be estimated at around 30% overall.

However, their identification (discoverability) depends on the quality of the indexing (metadata) and the functionality of the site.

Document descriptions vary from site to site. While on one site, reports are clearly identifiable, on another they are considered unpublished work or "other publications". You'll need to analyze the content closely before deciding how to proceed.

Similarly, depending on the interface, it's more or less easy to target certain types of documents or organizations.

In all cases, you need to check the status...