Note: Most of the e-books were created with the ibook. This software is very comfortable for producing e-books. Unfortunately these e-books can only be read with the mac software ibooks. That means that you only can read these e-books on MacBooks, iphones or ipads.
Sadly there is no software to convert in a simple way ibook-files to a epub3-file. epub3 is the last standard for e-books which can be read by a lot of e-book readers.
The Austrian team converted their e-books with a special software to epub3 format.

⇒to the joint project website with ebooks for ipad

⇒ to the ebooks for ipad and android from the Austrian team