DataCite is an international network, especially from public institutions worldwide, which support the access to research data
searches metadata from objects which are registered in DataCite with DOIs, e. g. research data (object type “dataset”). These metadata are partly also harvested by other services.
“more than 30 data providers among them the ICPSR and the CESSDA Service Providers GESIS, UKDA, SND, DDA, FSD, CSDA, and LiDA. Most of the metadata are harvested from metadata aggregators such as da|ra, DataCite and DataVerse.” (About)