Barbe, M. T. [P:(DE-HGF)0] ; Langen, Karl-Josef [P:(DE-Juel1)131777] ; Stoffels, G. [P:(DE-Juel1)131627] ; Coenen, Heinrich Hubert [P:(DE-Juel1)131816] ; Schroeter, M. [P:(DE-Juel1)VDB73300] ; Timmermann, L. [P:(DE-Juel1)VDB39909]