Merkel, R. [P:(DE-Juel1)128833] ; Endress, E. [P:(DE-HGF)0] ; Bayerl, S. [P:(DE-HGF)0] ; Prechtel, K. [P:(DE-HGF)0] ; Maier, C. [P:(DE-HGF)0] ; Bayerl, T. M. [P:(DE-HGF)0]