Collection
JSTOR Open Access Books
232
Directory of Open Access Books
108
O'Reilly
49
OAPEN
37
MIT Press eBook Archive
11
Eighteenth Century Collections Online / ECCO
10
Oxford University Press
5
ACS Symposium Series
3
Central European UP History & Political Science Backlist
3
JSTOR Books
3
Elsevier eBook collection Mathematics
2
Netlibrary
2
DeGruyter MPG Collection
1
Digi20
1
Editoria Italiana Online
1
Elsevier ScienceDirect eBooks
1
wiso-net eBooks
1