A reddit user ConcernedEarthling just posted his collection of UFO books in digital edition.
This is what he wrote:
This collection of books is what I have accumulated and organized over time to supplement my physical library at home, and it has been a useful collection to refer to others who have wanted some relevant reading.
It is actually one folder of a larger collection of online UFO materials, in what I call the UFO Reading Center, and it contains organized collections of magazines, studies, papers, and other materials. The entire collection is hosted on Google Drive..
I hope this is a useful and plentiful resource for those of you who may not have stumbled on it yet.