The Grey Literature regarding documents unconventional (York, 1978) and is not available through normal commercial channels (preprints, technical reports, official documents, dissertations and PhD, conference proceedings, statistics, bibliographies, etc.). The database is part of the European network OpenGrey (System for Information on Grey Literature in Europe) edited by the INIST-CNRS, an open-archive containing references related to "grey literature" produced in Europe and that the Library 'G. Marconi 'is the National Reference Centre for the Italian Grey Literature. To the implementation of the repertoire of Italian grey literature also collaborate certain structures and their representatives of the CNR scientific network.