1
by Ring, Gerhard
Published 2009
Nomos Verlagsgesellschaft mbH & Co. KG

2
by Ring, Gerhard
Published 2011
Nomos Verlagsgesellschaft mbH & Co. KG

3
by Ring, Gerhard
Published 2012
Nomos Verlagsgesellschaft mbH & Co. KG

4
by Ring, Gerhard
Published 2017
Nomos Verlagsgesellschaft mbH & Co. KG