From GreyNet International:
GreyNet International together with ISTI-CNR now provide over 400 published conference papers in the field of grey literature. Each is accompanied by a rich metadata record along with a system generated citation. This unique collection spans twenty international conferences in the GL-Series and is fully open access compliant. Papers in the last five conferences in this series have been assigned a minted DOI via DataCite and the remaining conference papers will retrospectively follow suit.
Direct to GreyGuide Database
Hat Tip: FEDLIB