If you're talking about *the* DLR test then it is the most documented pilots test in the world - and the most demanding. Is it in HAM or FRA or any other LH base? May-be Jade is buying a reduced one but basically it's most probably the same:
Maths, verbal reasoning, logical thinking, 3D puzzles, psycho-motoric tests. Hmm, English might as well asked ;-)
There are tons of books about the original DLR test. Have a look in Amazon. Most of them are in German.
Dani