1
by Rittmann, Günter
Published 2014
Nomos Verlagsgesellschaft mbH & Co. KG

2
by Heßler, Martina
Published 2020
Nomos Verlagsgesellschaft mbH & Co. KG

3
by Lytras, Miltiadis
Published 2019
MDPI - Multidisciplinary Digital Publishing Institute