Content Provider
DataCite Metadata Store (German National Library of Science and Technology)
4,667
Open Parks Network
2,175
Unknown
366
Washington State University: WSU Libraries Digital Collections
339
Hathi Trust Digital Library
157
PubMed Central (PMC)
119
Defense Technical Information Center: DTIC Technical Reports database
75
Copernicus Publications: E-Journals
68
University of the Pacific, McGeorge School of Law: Scholarly Commons
56
University of the Pacific: Scholarly Commons
56
University of Michigan: Digital Collections
50
University of Florida: Digital Library Center
48
MDPI Open Access Publishing
45
University of Nebraska-Lincoln: DigitalCommons@UNL
41
Érudit.org (Université Montréal)
38
BioOne Online Journals
35
Project Gutenberg (PG)
34
North Dakota State University (NDSU): Digital Horizons
27
Arca (BC's Digital Treasures)
23
HighWire Press (Stanford University)
23
The Online Books Page (Penn Libraries, University of Pennsylvania)
21
Utah State University: DigitalCommons@USU
21
Central Washington University: ScholarWorks
17
University of New Hampshire: Scholars Repository
17
Digital Collections of Colorado (Colorado State University)
15
Mountain Scholar (Digital Collections of Colorado and Wyoming)
15
Wilfrid Laurier University, Ontario: Scholars Commons@Laurier
15
Boise State University: Scholar Works
14
The University of Western Ontario: Scholarship@Western
14
The University of Maine: DigitalCommons@UMaine
12
UNBC's Digital Institutional Repository (University of Northern British Columbia)
11
University of South Florida St. Petersburg: Digital USFSP
9
Digitale Landesbibliothek Berlin (Zentral- und Landesbibliothek Berlin)
8
Environmental Protection Agency (EPA): Science Inventory
8
The University of Southern Mississippi: The Aquila Digital Community
8
UQAM - Université du Québec à Montréal: archipel
8
Saint Mary's University, Halifax: Institutional Repository
7
Western Washington University: CEDAR (Contributing to Education through Digital Access to Research)
7
Brigham Young University (BYU): ScholarsArchive
6
CyberLeninka (Scientific Electronic Library)
6
Digital Commons University of South Florida (USF)
6
University of Massachusetts: ScholarWorks@UMass Amherst
6
University of San Diego: Digital@USanDiego
6
APS Digital Library (American Philosophical Society)
5
University of Illinois at Urbana-Champaign: UIUC Digitized Books
5
York University Toronto, Osgoode Hall Law School: Osgoode Digital Commons
5
David Rumsey Historical Map Collection (Cartography Associates)
4
Hunter Library Digital Collections (Western Carolina University)
4
Michigan State University College of Law: Digital Commons
4
Princeton Theological Seminary: Theological Commons
4
more ...