Heyes, W.J. [P:(DE-HGF)0] ; Vaughan, G. [P:(DE-HGF)0] ; Allen, G. [P:(DE-HGF)0] ; Volz-Thomas, A. [P:(DE-Juel1)6742] ; Pätz, H.-W. [P:(DE-Juel1)16214] ; Busen, R. [P:(DE-HGF)0]