befb8e68_eBook_Options_for_Libraries__Source
[Name] Open Library [Ownership] Yes [DRM-free] No [Copyright/License] Fair Use/First Sale [Distribution] Hosted by Open Library: a set of over 200,000 ebooks is available for “in library” lending, and a set of 10,000 is available for “open lending” [Format] ePub, PDF, in-browser [Cost] Free [Examples] Over 1,000 participating libraries [Source] 
Print-based books digitized by Open Library and converted to eBooks. Open Library has also bought ebooks directly from a few publishers.
eBook Options for Libraries
Source