For retrieving, preserving and managing digital documents of gray literature and its metadata a sophisticated software system must be used. CDS Invenio is a software solution for the needs of NRGL – for the central repository, which collects and the grey literature and makes it accessible and for the co-working organizations, which produce the grey literature. Its complexity, flexibility and open-source solution ensure fulfilling of nearly all requirements that NRGL have for this system.