Your can use audiobook-dl (I’m the author). You can download from:

• eReolen
• Mofibo
• Nextory
• Podimo
• Saxo

They all have danish books. Try MyAnonyMouse otherwise.

Okay, that sound amazing, i will check if it exists as an app on true nas, otherwise I’ll do my best to find a solution, though ereolen is already free if you are part of a library here in Denmark, then you can borrow a few books every month, but the interface works like shit, so it is a lot better to just download them, then you also has no cap on the amount you get