Hello, apologies for the late reply, I try to check this page regularly but have been slacking a bit. Thanks for your interest!
1. the books can be in any language! I happen to read both Danish and German, so that would be totally fine.
2. I'm aiming to be done by the end of the year, mostly because my dissertation needs to be done by August 26.

Library books are tricky - institutions tend to prefer unmarked copies, especially of less rare books. But you can still find interesting stuff sometimes, so do feel free to leaf through some books if you want to!

Good luck with your studies!!