Content Provider
Cambridge University Press
33
Unknown
3
DataCite Metadata Store (German National Library of Science and Technology)
2
David Rumsey Historical Map Collection (Cartography Associates)
2
University of Kent: KAR - Kent Academic Repository
2
Alfred Wegener Institute for Polar- and Marine Research (AWI): ePIC (electronic Publication Information Center)
1
Biblioteca Virtual de Defensa (BVD - Ministerio de Defensa de España)
1
OceanRep (GEOMAR Helmholtz Centre für Ocean Research Kiel)
1
Oxford University Press (via Crossref)
1
University of Wollongong, Australia: Research Online
1