Export books from iBooks

Aloha,

I asked similar question long time ago, but nobody could provide a solution.

How to export MY books form iBooks, if you are using iCloud/ iCloud Drive for iBooks?

Setup is:

macOs 10.12.5

iCloud activated

iCloud Drive activated for iBooks

I know the local path of the content:

~/Library/Mobile Documents/iCloud~com~apple~iBooks

and with a simple:

cp -r ~/Library/Mobile Documents/iCloud~com~apple~iBooks ~/Documents/ALLMYBOOKS

it would be possible to get a copy.

But does anyone else an "official way" with using iBooks or Finder?

Thanks

Marcel