Collection
Directory of Open Access Books
149
National Center for Biotechnology Information
104
OAPEN
28
Digi20
9
Making of the Modern World
7
Eighteenth Century Collections Online / ECCO
5
Springer Book Archives -2004
4
Springer eBooks 2005-
4
Nomos
3
Mohr Siebeck eBooks
2
Edward Elgar eBooks Collection Business & Economics
1