Content Provider
DataCite Metadata Store (German National Library of Science and Technology)
140
NOAA NCEI Environmental Data Archive (via DataONE)
23
Defense Technical Information Center: DTIC Technical Reports database
3
Directory of Open Access Journals: DOAJ Articles
2
Dryad Digital Repository (Duke University)
2
Unknown
2
NASA Technical Reports Server (NTRS)
1
OceanRep (GEOMAR Helmholtz Centre für Ocean Research Kiel)
1
Polar Research
1
ScholarWorks@UNIST (Ulsan National Institute of Science and Technology)
1
University College London: UCL Discovery
1
University of Stavanger: UiS Brage
1