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DataCite
4
Directory of Open Access Journals: DOAJ Articles
4
University of California: eScholarship
3
Cambridge University Press
2
ScienceDirect (Elsevier - via Crossref)
2
Clark University: Clark Digital Commons
1
DIAL@UCLouvain (Université catholique de Louvain)
1
DIAL@USL-B (Université Saint-Louis, Bruxelles)
1
NASA Technical Reports Server (NTRS)
1
University of Colorado, Boulder: CU Scholar
1
Utrecht University Repository
1