Tsoneva, N. [P:(DE-HGF)0] ; Bhike, M. [P:(DE-HGF)0] ; Krishichayan, K. [P:(DE-HGF)0] ; Lenske, H. [P:(DE-HGF)0] ; Rusev, G. [P:(DE-HGF)0] ; Tonchev, A. [P:(DE-HGF)0] ; Tornow, W. [P:(DE-HGF)0]