Variety of literature (in Hungarian):
DOG - Winfried Nouč (translated in 1995)
The wonderful great dane - A csodálatos német dog - Szinák - Volosz (2002)
Great dane - Német dog - István Veres (2001)

Others:
Dogpsychology - Jan Fennel
A dog's best friend - Jan Fennel
These books provides essential help on behaviour and keeping problems of dogs. The writer illustrates the solutions with cases occured in real life.

Cesar's way - Cesar Millan & Melissa Jo Peltier

The real horse Whisperer - Monty Roberts
Horses and humans - Monty Roberts
Shy Boy - Monty Roberts
Horses in my life - Monty Roberts
These four books are not about danes, not even about dogs. Apart from that, they are a must to read. Unfortunately they can only be found in libraries or second hand bookshops.

Thanks to Ami for attracting our attention on Jan Fennel's and Monty Roberts' work.